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<title>Wt Release notes</title>
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<h1>Wt Release notes</h1>

This file lists important notes on migrating existing applications to
newer version of Wt. It lists changes in the library that may break
the way you build Wt, the way you configure Wt or the Wt API and
behaviour.

<h2>Release 4.0.0 (September 19, 2017)</h2>
<p>
  This release has all of the added features of Wt 3.3.8, but comes with many notable changes. In general,
  Wt 4 employs the more modern C++ style of C++11 and beyond. Support for compilers
  without sufficient C++11 support is dropped competely. Wt 4 aligns more with the
  <a href="https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md">C++ Core Guidelines</a>
  in a pragmatic way, while keeping the API familiar.
</p>
<h3>New features since Wt 3.3.8</h3>
<dl>
  <dt>Microsoft SQL Server backend for Wt::Dbo</dt>
  <dd>We've added Microsoft SQL Server support to Wt::Dbo, making it the sixth
      backend we support, alongside Sqlite, PostgreSQL, MySQL (and MariaDB),
      Firebird, and Oracle (not part of the open source Wt because of licensing).
      With this addition, Wt::Dbo now supports most commonly used relational database management systems.
      It's based on ODBC and works with Microsoft's ODBC Driver
      for SQL Server. With unixODBC, Linux and macOS are also supported.</dd>
  <dt>Added support for listening on multiple interfaces and ports to wthttp</dt>
  <dd>With the multivalued <tt>--http-listen</tt> and <tt>--https-listen</tt> options,
      you can now listen on multiple interfaces and ports. For example, if you want to
      listen on port 8080 on all IPv4 and IPv6 interfaces, you can use:
      <div class="fragment">
	<div class="line"><tt>--http-listen 0.0.0.0:8080 --https-listen [0::0]:8080</tt></div>
      </div>
      <tt>--http-listen</tt> and <tt>--https-listen</tt> obsolete the
      <tt>--http-address</tt>, <tt>--http-port</tt>, <tt>--https-address</tt>, and <tt>--https-port</tt>
      options.</dd>
</dl>
<h3>Changes in Wt's memory model</h3>
<p>
Like before, the parent widget (e.g. a <a href="classWt_1_1WContainerWidget.html">WContainerWidget</a>) owns
its child widgets. This has not changed. Wt 4 makes ownership transfers more clear by using <tt>std::unique_ptr</tt>
There are no more owning raw pointers in Wt's public API.
</p>
<p>
By consequence of using <tt>unique_ptr</tt>, constructors no longer take a <tt>parent</tt> argument. For
convenience, <a href="classWt_1_1WContainerWidget.html#a3341360fc6cc1e86c1a42a3a54d9e0c7">addWidget()</a>
now returns a (non-owning) raw pointer. Instead of doing:
<div class="fragment">
  <div class="line"><span class="comment"><tt>// parent is a Wt::WContainerWidget*</tt></span></div>
  <div class="line"><tt>Wt::WPushButton *button = new Wt::WPushButton("Click me", parent); <span class="comment">// Wt 3: parent owns the button</span></tt></div>
</div>
or:
<div class="fragment">
  <div class="line"><tt>Wt::WPushButton *button = new Wt::WPushButton("Click me");</tt></div>
  <div class="line"><tt>parent-&gt;addWidget(button); <span class="comment">// Wt 3: ownership is transferred to parent through addWidget</span></tt></div>
</div>
You can now do:
<div class="fragment">
  <div class="line"><span class="comment"><tt>// Wt 4 (with C++14's std::make_unique)</tt></span></div>
  <div class="line"><tt>Wt::WPushButton *button = parent-&gt;addWidget(std::make_unique&lt;Wt::WPushButton&gt;("Click me"));</tt></div>
</div>
<tt>Wt::cpp14::make_unique</tt> can be used instead of <tt>std::make_unique</tt> if C++14 support is unavailable.
</p>
<p>
Some classes were changed from the old single ownership
model to shared ownership through <tt>std::shared_ptr</tt>, like models (<a href="classWt_1_1WAbstractItemModel.html">WAbstractItemModel</a>, <a href="classWt_1_1Chart_1_1WAbstractChartModel.html">WAbstractChartModel</a>, and derivates) and <a href="classWt_1_1WValidator.html">validators</a>.
</p>
<p>
<a href="classWt_1_1Core_1_1observing__ptr.html">Wt::Core::observing_ptr</a> was introduced. This pointer will
be notified when the object it points to is deleted. <tt>observing_ptr</tt>s are intended to be used within the
scope of a <a href="classWt_1_1WApplication.html">WApplication</a> and are not thread safe. Every
<a href="classWt_1_1WObject.html">WObject</a> (and by consequence, every <a href="classWt_1_1WWidget.html">widget</a>)
is an <a href="classWt_1_1Core_1_1observing_ptr.html">observable</a>, so its lifetime can be observed with
an <tt>observing_ptr</tt>. Their use is entirely optional, but they may be useful when the lifetime of an
object is not always clear.
</p>
<h3>Header files now end in .h</h3>
Wt 3 used extensionless headers. This confuses many editors and IDEs.
For Wt 4, the <tt>.h</tt> extension was added, and using the old style headers is deprecated. You can use the
Python script <a href="https://github.com/emweb/wt/blob/wt4/migrate/wt4_add_h_to_includes.py">migrate/wt4_add_h_to_includes.py</a> to help update your Wt includes.
<h3>Enums replaced by enum classes</h3>
Many enums were replaced with enum classes, and many have been moved from class scope to namespace scope, e.g.:
<div class="fragment">
  <div class="line"><tt>enum SelectionMode {</tt></div>
  <div class="line"><tt>&nbsp;&nbsp;NoSelection = 0,</tt></div>
  <div class="line"><tt>&nbsp;&nbsp;SingleSelection = 1,</tt></div>
  <div class="line"><tt>&nbsp;&nbsp;ExtendedSelection = 3</tt></div>
  <div class="line"><tt>};</tt></div>
</div>
became:
<div class="fragment">
  <div class="line"><tt>enum class SelectionMode {</tt></div>
  <div class="line"><tt>&nbsp;&nbsp;None = 0,</tt></div>
  <div class="line"><tt>&nbsp;&nbsp;Single = 1,</tt></div>
  <div class="line"><tt>&nbsp;&nbsp;Extended = 3</tt></div>
  <div class="line"><tt>};</tt></div>
</div>
Some enums were preserved in places were the added verbosity
was undesirable, like the <a href="group__dbo.html#ga1d0ec6819b1bf5b7a88ad030b91ca564">Wt::Dbo::RelationType</a> enum.
<h3>Replacements for Boost</h3>
    Many features of Boost that Wt relied on were made obsolete by C++11. Many other Boost features have been replaced
    with C++11-based alternatives.

    <dl>
      <dt>Choice between Boost.Asio and standalone Asio</dt>
      <dd>
        The CMake option <tt>WT_ASIO_IMPLEMENTATION</tt> allows to choose between <tt>boost</tt> and <tt>standalone</tt>
	Asio.</dd>
      <dt>Removal of Boost usage in Wt headers</dt>
      <dd>
        If standalone Asio is used, the installed headers of Wt no longer include any Boost headers.
	The Windows builds of Wt 4 will from now on no longer include Boost,
	including only the standalone Asio headers instead. This just about halves the size of the installer.
	If you want to use Boost, you'll have to provide your own. You can find prebuilt Boost binaries for Windows
	<a href="https://sourceforge.net/projects/boost/files/boost-binaries/">here</a>.
      </dd>
      <dt>Boost.Date_Time was replaced with Howard Hinnant's <tt>std::chrono</tt>-based date implementation</dt>
      <dd>
      The author of the <tt>std::chrono</tt> standard has created a
      <a href="https://github.com/HowardHinnant/date">library for dates and time zones</a>.
	This library is proposed for inclusion into the C++ standard in the future. For now, Wt includes
	this date and time zone library (at this moment, this is version 2.2). This is used for all time-related
	classes, like <a href="classWt_1_1WDate.html">WDate</a>,
	<a href="classWt_1_1WTime.html">WTime</a>, <a href="classWt_1_1WDateTime.html">WDateTime</a>,
	and <a href="classWt_1_1WLocalDateTime.html">WLocalDateTime</a>.
      </dd>
      <dt>
        Boost.Any replaced by <tt>Wt::cpp17::any</tt>
      </dt>
      <dd>
        <a href="classWt_1_1WStandardItemModel.html">WStandardItemModel</a> relied heavily on
	<tt>boost::any</tt>. This was replaced with <tt>Wt::cpp17::any</tt>. You can choose the
	implementation of <tt>any</tt> to use with the CMake option <tt>WT_CPP17_ANY_IMPLEMENTATION</tt>.
	Valid options are:
	<ul>
	  <li><a href="https://github.com/thelink2012/any">thelink2012</a>: this is the default implementation, included in Wt</li>
	  <li><tt>experimental</tt> for <tt>std::experimental::any</tt></li>
	  <li><tt>std</tt> for C++17's <tt>std::any</tt></li>
	</ul>
      </dd>
      <dt>Boost.Signals2 replaced with own implementation</dt>
      <dd>
        <p>
          Wt did not use many of the features of Boost.Signals2. Since C++11, many more efficient alternatives
	  have been created. Wt 4's implementation, based on
	  <a href="https://testbit.eu/cpp11-signal-system-performance/">this blog post</a>, offers better performance
	  and more understandable stack traces. It's now no longer necessary to
	  use <tt>std::bind</tt> with lambda functions, e.g.:
	  <div class="fragment"><div class="line"><tt>button-&gt;clicked().connect(std::bind([]{ std::cout &lt;&lt; "Clicked!" &lt;&lt; std::endl; })); <span class="comment">// Wt 3</span></tt></div></div>
	  can be changed to:
	  <div class="fragment"><div class="line"><tt>button-&gt;clicked().connect([]{ std::cout &lt;&lt; "Clicked!" &lt;&lt; std::endl; }); <span class="comment">// Wt 4</span></tt></div></div>
	</p>
	<p>
	  Boost.Signals2, together with <tt>boost::bind</tt>, allowed you to automatically disconnect slots
	  when one of their bound arguments was deleted, if the argument was a derived class of
	  <tt>boost::signals2::trackable</tt>. In Wt 4, this is no longer the case. Instead, you
	  can provide a target <a class="classWt_1_1WObject.html">WObject</a> as the first argument to
	  the connect function, and Wt will disconnect the slot when the target <tt>WObject</tt> is deleted.
	</p>
	<p>
	  <tt>WApplication::bind</tt> has been removed, and instead
	  <a href="classWt_1_1Core_1_1observable.html#a8ef9ce1dc22e3bae13e198b27e6b64cc">observable::bindSafe</a>
	  was introduced. <tt>bindSafe</tt> will guard the <tt>observable</tt>, returning a function
	  object that doesn't do anything if the <tt>observable</tt> has been deleted.
	</p>
      </dd>
      <dt>Other Boost libraries obsoleted by C++11</dt>
      <dd>Boost.Thread, Boost.Regex and Boost.Random were mostly replaced by their STL counterparts. Only
          Boost.Thread is used internally in Wt 4 because Wt uses some mutex functionality that's not part of
          C++11.</dd>
    </dl>
  <h3>Other changes:</h3>
    <ul>
      <li>
	<a href="classWt_1_1ItemDataRole.html">ItemDataRole</a> is now a class instead of an enum.
      </li>
      <li>
	Wt 4 assumes that <tt>std::string</tt> is UTF-8 encoded by default, so
	<a href="classWt_1_1WString.html#a64d17e31e557208ab8d8ea765c1e52b8">WString(std::string)</a>
	will assume that the argument is UTF-8 encoded. Overloads for new C++11 string types
	(<tt>std::u16string</tt>, <tt>std::u32string</tt>) have been added.
      </li>
      <li>
	Intervals and other durations previously indicated by <tt>int</tt>s have been replaced by
	<tt>std::chrono::duration</tt>s, e.g. in 
	<a href="classWt_1_1WIOService.html#a5e445e207ee36f75cea4ba7ae321d7dc">WIOService::schedule()</a> or
	<a href="classWt_1_1Http_1_1Client.html#a84856aabdef30b9e91bb3c4d30b9ecd1">Wt::Http::Client::setTimeout()</a>.
      </li>
      <li>
	<a href="classWt_1_1WBoxLayout.html">WBoxLayout</a> is now implemented with flexbox instead of JavaScript
	by default. Wt will fallback to the old JavaScript implementation when functionality unavailable in
	the flexbox implementation is used, use
	<a href="classWt_1_1WLayout.html#a9cd0547c710e357e4c688ccfdb790d8f">WBoxLayout::setPreferredImplementation</a>
	to set a preferred implementation.
      </li>
    </ul>
  <h3>Removal of deprecated functionality</h3>
    <ul>
      <li>
	Everything that was marked as deprecated in Wt 3.3.7 has been removed,
	including <tt>Wt::Ext</tt>.
      </li>
      <li>
	<tt>WScrollArea</tt> was removed, use CSS or
	<a href="classWt_1_1WContainerWidget.html#af3d9510f569deed060689aa509ecc831">WContainerWidget::setOverflow()</a> instead.
      </li>
    </ul>

<h2>Release 3.3.8 (August 16, 2017)</h2>
<p>
  This release consists of bug fixes and some new features:
</p>
<dl>
  <dt>
    OpenID Connect support
  </dt>
  <dd>
    As we've previously announced
    <a href="https://www.webtoolkit.eu/wt/blog/2017/06/20/announcing_openid_connect_support_in_wt">on our blog</a>,
    Wt now supports OpenID Connect. All you need to do to use any OpenID Connect based service is
    configure a <a href="classWt_1_1Auth_1_1OidcService.html">Wt::Auth::OidcService</a>. You can also make your
    own OpenID Connect identity provider. Check out the accompanying
    <a href="https://github.com/emweb/wt/tree/master/examples/feature/oidc">OpenID Connect feature example</a>.
  </dd>
  <dt>
    On Windows: font support based on DirectWrite
  </dt>
  <dd>
  <p>Wt 3.3.7 already introduced the Direct2D backend for <a href="classWt_1_1WRasterImage.html">WRasterImage</a>.
    Wt 3.3.8 further expands
    on this by adding DirectWrite-based font support. This means that Wt 3.3.8 will be able to
    select the appropriate fonts for every glyph, without requiring Pango. Pango was always
    difficult to distribute on Windows, so we never included Pango in the binary distribution, relying on
    very basic font support instead, replacing unknown characters by question marks. Now, you
    can expect much better Unicode support with DirectWrite on Windows.</p>
    <p>This means that the binary release of Wt on Windows is now built with Direct2D and DirectWrite.</p>
  </dd>
  <dt>
    Wt::Dbo: added <a href="structWt_1_1Dbo_1_1sql__value__traits.html">sql_value_traits</a> for
    <a href="classWt_1_1Json_1_1Object.html">Wt::Json::Object</a> and
    <a href="classWt_1_1Json_1_1Array.html">Wt::Json::Array</a>.
  </dt>
  <dd>
    <p>Quite often, the need arises to store some unindexed data with arbitrary structure in a database.
       A common solution is to store JSON as a string. To facilitate this, we've included implementations
       of <a href="structWt_1_1Dbo_1_1sql_value_traits.html">sql_value_traits</a> for
       <a href="classWt_1_1Json_1_1Object.html">Wt::Json::Object</a> and
       <a href="classWt_1_1Json_1_1Array.html">Wt::Json::Array</a> in
       <tt>Wt/Dbo/WtSqlTraits</tt>. This allows you to store <tt>Wt::Json</tt> Objects and Arrays
       just like you any other field.</p>
    <p>Additionally, we've made the <tt>Wt::Json</tt> API a bit more friendly, by adding support
    for initializer lists (when using C++11), and implicit constructors for
    <a href="classWt_1_1Json_1_1Value.html">Wt::Json::Value</a>
    from 
    <a href="classWt_1_1Json_1_1Object.html">Wt::Json::Object</a> and
    <a href="classWt_1_1Json_1_1Array.html">Wt::Json::Array</a>.</p>
  </dd>
  <dt>
    Added <tt>&lt;allowed-hosts&gt;</tt> configuration option for CORS
  </dt>
  <dd>
    Wt used to allow almost any origin, to allow Wt applications to be embedded in any page using
    WidgetSet mode. Although Wt encodes session IDs in URLs rather than cookies by default, this
    could still pose a security risk in some cases. In Wt 3.3.8, CORS support has been updated:
    Wt now only allows cross-origin resource sharing for WidgetSet entry points, and trusts no
    host by default. You can specify the allowed hosts using the <tt>&lt;allowed-hosts&gt;</tt>
    tag in the configuration file. Using <tt>&lt;allowed-hosts&gt;*&lt;/allowed-hosts&gt;</tt> 
    restores the old behaviour.
  </dd>
  <dt>
    Other small improvements:
  </dt>
  <dd>
    <ul>
      <li>Any <tt>boost::asio::io_service</tt> can now be used with <a href="classWt_1_1Http_1_1Client.html">Wt::Http::Client</a>,
	  instead of just <a href="classWt_1_1WIOService.html">Wt::WIOService</a>.</li>
      <li>Added support for <tt>PATCH</tt> requests in <a href="classWt_1_1WResource.html">WResource</a> and
	<a href="classWt_1_1Http_1_1Client.html">Wt::Http::Client</a>,
	next to <tt>GET</tt>, <tt>POST</tt>, <tt>PUT</tt>, and <tt>DELETE</tt>.
      <li>wthttp connector: added support for forward secrecy with the <tt>--ssl-prefer-server-ciphers</tt> option.</li>
      <li>Added the <tt>num-session-threads</tt> configuration parameter, to set the amount of threads per session when
	  using dedicated process mode. By default, the main process and the session threads use the same amount of threads.</li>
      <li>The <a href="https://github.com/emweb/wt/tree/master/examples/te-benchmark">te-benchmark</a>
	  example was added, implementing the TechEmpower framework benchmarks.
          This example also demonstrates how Wt can be used to write RESTful services. Improved, less verbose, support for
          RESTful services is planned in a future release.</li>
      <li>Added <a href="classWt_1_1Dbo_1_1FixedSqlConnectionPool.html#a955e2ce03d8d45e8738f6ff718614601">Wt::Dbo::FixedSqlConnectionPool::setTimeout()</a>, to set a timeout for obtaining a connection.</li>
      <li>Added <a href="classWt_1_1Dbo_1_1backend_1_1Postgres.html#acb13461474cc43bc9e8a51b844a051f3">Wt::Dbo::backend::Postgres::setTimeout()</a>, to set a timeout for queries.</li>
      <li>Added libunwind support for printing stacktraces. Enable this with the <tt>ENABLE_UNWIND</tt> CMake option.</li>
    </ul>
  </dd>
</dl>

<h2>Release 3.3.7 (March 31, 2017)</h2>
<p>
  This release fixes many bugs, but also introduces some new features:
</p>
<dl>
  <dt>
    <a href="classWt_1_1WFileDropWidget.html">WFileDropWidget</a>
  </dt>
  <dd>
    The WFileDropWidget is a new widget that allows you to upload a file or multiple files by dragging them onto an area.
  </dd>
  <dt>
    Scroll visibility
  </dt>
  <dd>
    Some applications require you to know whether a widget is currently visible within the viewport, or whether it is
    scrolled out of view, e.g. to load more content as you scroll down the page. You can now enable scroll visibility
    detection with
    <a href="classWt_1_1WWidget.html#a5d403e0390841df77a23445b28044d5d">WWidget::setScrollVisibilityEnabled(bool)</a>,
    and react to changes in visibility with
    <a href="classWt_1_1WWidget.html#aa5ce605dd465e06f3e3c2dbce2a4098e">WWidget::scrollVisibilityChanged()</a>.
    A new scrollvisibility feature example has been added to demonstrate this infinite scrolling application.
  </dd>
  <dt>
    Touch events
  </dt>
  <dd>
    Although Wt already supported touch interactions in the charting library, touch events were previously
    not exposed by Wt. Now,
    we've added <a href="classWt_1_1WTouchEvent.html">WTouchEvent</a>, and the touchStarted, touchEnded, and touchMoved
    events have been added to
    <a href="classWt_1_1WInteractWidget.html">WInteractWidget</a>.
    Also, <a href="classWt_1_1WInteractWidget.html#a556c14d02388720b1d95b2149be2e867">draggable widgets</a> can now also
    be dragged after a long press, and you can select a range using a double touch in
    <a href="classWt_1_1WTableView.html">WTableView</a> and <a href="classWt_1_1WTreeView.html">WTreeView</a>.
  </dd>
  <dt>
    Combined session tracking mode
  </dt>
  <dd>
    <p>
      The default session tracking method for Wt is URL rewriting, using JavaScript to hide the session id from
      the address bar. Alternatively, cookies can be used with the Auto option, falling back to URL rewriting when
      cookies are not available. However, the cookie-based method did not allow for multiple sessions within the
      same browser.
    </p>
    <p>
      In order to make the URL rewriting method with requirement 6.5.10 of the PCI Data Security Standard, while not
      sacrificing the ability to have multiple sessions, a new Combined session tracking strategy has been added.
      Wt already makes it difficult to steal a session when the session id is discovered, but resources are not as
      protected. The Combined session tracking strategy uses URL rewriting in combination with a cookie that is shared
      between sessions as an extra measure against session hijacking. This is the most secure strategy, but it will
      deny access if cookie support is not available.
    </p>
  </dd>
  <dt>
    Wraparound for <a href="classWt_1_1WSpinBox.html">WSpinBox</a> and <a href="classWt_1_1WTimeEdit.html">WTimeEdit</a>
  </dt>
  <dd>
    WSpinBox will now wrap around from its maximum to its minimum if you <a href="classWt_1_1WSpinBox.html#a08413e777fefab00e36dc8d6c492bda5">enable wraparound</a>. WTimeEdit will take advantage of this feature by default.
  </dd>
  <dt>
    On Windows: Direct2D implementation of WRasterImage
  </dt>
  <dd>
    We've added another implementation for WRasterImage on Windows: Direct2D. When building Wt, this
    implementation will be enabled by default. This allows to remove the dependency on GraphicsMagick or
    Skia on Windows, simplifying the build process.
  </dd>
  <dt>
    Some minor extra features:
  </dt>
  <dd>
    <ul>
      <li>
	It's now possible to retrieve a vector of all request headers with <a href="classWt_1_1Http_1_1Request.html#a0afe45bf93bb77270a85c75ca67cd521">Wt::Http::Request::headers()</a> in <a href="classWt_1_1WResource.html#a3a740f8cc29e2e6e4e58defc9c88b8b6">handleRequest</a> when implementing a WResource. It is still recommended, and more efficient, to use <a href="classWt_1_1Http_1_1Request.html#ade2596aa6802a63e21460094ea30a4d9">headerValue</a>, but retrieving a vector of all headers could be useful for debugging purposes.
      </li>
      <li>
	In an effort to reduce the amount of JavaScript generated by the charting API, the
	<a href="classWt_1_1WPainter.html#abccad19493d7461ca08c9e50ad7326f1">WPainter::drawStencilAlongPath()</a>
	method was added to WPainter.
      </li>
      <li>
	Previously, WDialogs were movable by default. It's now possible to disable this with 
	<a href="classWt_1_1WDialog.html#afbccf557a0343591f3087c9a0a9b7051">WDialog::setMovable()</a>.
      </li>
    </ul>
  </dd>
</dl>

<h2>Release 3.3.6 (July 13, 2016)</h2>
<p>
 This release has a focus on bug fixes and some new features:
</p>
<dl>
  <dt>
    Support for WebSocket compression in wthttp
  </dt>
  <dd>
    WebSocket traffic is now compressed, if possible.
  </dd>
  <dt>
    Time entry improvements
  </dt>
  <dd>
    <a href="classWt_1_1WTimeEdit.html">WTimeEdit</a> now supports AM/PM in its format,
    <a href="classWt_1_1WTimeValidator.html">WTimeValidator</a> now allows to select a minimum
    and maximum time and supports multiple formats,
    <a href="classWt_1_1WTimePicker.html">WTimePicker</a> can now work up to
    millisecond precision, and is now rendered with spinboxes.
  </dd>
  <dt>
    Skia version updated
  </dt>
  <dd>
    The Skia backend for <a href="classWt_1_1WRasterImage.html">WRasterImage</a> is now compatible with more recent versions of Skia. If you need
    to support an older version of Skia, use <tt>-DWT_SKIA_OLD=ON</tt>. The Skia version of the Windows builds
    has been updated from 394c7bb to 834d9e1.
  </dd>
  <dt>
    Wt::Dbo
  </dt>
  <dd>
    <ul>
      <li>
      It's now possible to mark foreign keys as literal with a &ldquo;&gt;&rdquo; prefix, so Wt::Dbo can better map to
      an existing schema. Note that for consistency, this also means that the schema generated for ManyToMany relationships
      has been changed to include the id column names if a joinId has been specified. If you specify a joinId for ManyToMany
      relationships, you'll have to change it to include a &ldquo;&gt;&rdquo; before it in order to keep the same database schema.
      </li>
      <li>
	The <tt>size</tt> argument of <a href="group__dbo.html#gac089020eff000d9e2c4ef72cf715bd21">belongsTo()</a> has been
	removed, since it served no actual purpose.
      </li>
    </li>
  </dd>
  <dt>
    Scroll position
  </dt>
  <dd>
    It's now possible to retrieve the scroll position of a
    <a href="classWt_1_1WContainerWidget.html">WContainerWidget</a>
    with
    <a href="classWt_1_1WContainerWidget.html#a0a7ce553b2b5107412a3bed8700355cb">scrollTop()</a>
    and
    <a href="classWt_1_1WContainerWidget.html#a9a60d382fcd1490081087ce4f3649864">scrollLeft()</a>.
  </dd>
  <dt>
    Invalidation of stateless slots
  </dt>
  <dd>
    <a href="classWt_1_1WObject.html#a6dde4ce1e833a9966709daf3c0dedc9f">WObject::isNotStateless()</a>
    has been added, so functions called from functions that are marked as stateless can unmark
    it as stateless, reverting to plain server-side dynamic UI updates.
  </dd>
  <dt>
    <a href="classWt_1_1Auth_1_1Dbo_1_1UserDatabase.html">Auth::Dbo::UserDatabase</a>
  </dt>
  <dd>
    The <a href="classWt_1_1Auth_1_1Dbo_1_1UserDatabase.html">Dbo UserDatabase</a> implementation now
    compares e-mail addresses case insensitively. The <a href="classWt_1_1Auth_1_1AuthService.html">AuthService</a>
    can be passed in the constructor, so the <a href="classWt_1_1Auth_1_1Dbo_1_1UserDatabase.html">UserDatabase</a>
    knows whether the IdentityPolicy is EmailAddressIdentity.
  </dd>
  <dt>
    Charting library
  </dt>
  <dd>
    There have been many bug fixes and improvements to the charting library and the interactive features
    introduced in Wt 3.3.5:
    <ul>
      <li>Series <a href="classWt_1_1Chart_1_1WCartesianChart.html#ad05997dbc2d59862e38272985abda9a9">can be selected</a>
      on a <a href="classWt_1_1Chart_1_1WCartesianChart.html">WCartesianChart</a>.
      LineSeries <a href="classWt_1_1Chart_1_1WCartesianChart.html#a6078b67f146e686bd482d846dfe463cb">can be manipulated</a>.</li>
      <li><a href="classWt_1_1Chart_1_1WAxis.html#a16d188d56c2b62b7b3f2ddb6fa96d7cc">WAxis::setZoom()</a> and
	  <a href="classWt_1_1Chart_1_1WAxis.html#a2f6a11d9d47036f8806c5a8412dfd24c">WAxis::setPan()</a>
	  have been deprecated in favor of the easier to use
	  <a href="classWt_1_1Chart_1_1WAxis.html#a0be187399e7cb4877f2c5e3837eba6ea">WAxis::setZoomRange()</a>.
	  You can listen to changes in zoom range with the
	  <a href="classWt_1_1Chart_1_1WAxis.html#a7e432917f0f23f18db3a043397a81904">WAxis::zoomRangeChanged()</a> signal.</li>
       <li>Series set as hidden will still be shown on a <a href="classWt_1_1Chart_1_1WAxisSliderWidget.html">WAxisSliderWidget</a>.
	   The typical application for this is to show a coarse model on the slider widget, and a more detailed one on the chart.</li>
      <li>
	  In order to provide better performance for charts containing a lot of data, the charting library has been
	  overhauled to use <a href="classWt_1_1Chart_1_1WAbstractChartModel.html">WAbstractChartModel</a>s,
	  instead of <a href="classWt_1_1WAbstractItemModel.html">WAbstractItemModel</a>s, avoiding the use of
	  boost::any. The <a href="classWt_1_1Chart_1_1WStandardChartProxyModel.html">WStandardChartProxyModel</a>
	  wraps a <a href="classWt_1_1WAbstractItemModel.html">WAbstractItemModel</a> so that those can still be used with charts.
	  Note that this changes the return type of the
	  <a href="classWt_1_1Chart_1_1WAbstractChart.html#a477522bb1720fb20006c81be455b3366">WAbstractChart::model()</a> method.
      </li>
      <li>A chart's axes can now be <a href="classWt_1_1Chart_1_1WAxis.html#a2bb7c8ec67ed2ff0b57953ea40cd87ef">inverted</a>.
      <li>Stacked series: negative values are now stacked separately from positive values.</li>
      <li><a href="classWt_1_1Chart_1_1CurveLabel.html">Curve labels</a> can now be drawn on charts, so that curves,
          or certain points on curves, can be labeled.</li>
	  <li><a href="classWt_1_1Chart_1_1WAxis.html#afca24479982f10759be69703de5f4cd4">WAxis::getLabelTicks()</a>
	  has been modified with an argument
          <a href="structWt_1_1Chart_1_1AxisConfig.html">AxisConfig</a>, so that different axis ticks can be drawn depending
	  on the side that the axis is dawn on, or the zoom level it is drawn at. This is a breaking change if you override getLabelTicks.
	  <a href="classWt_1_1Chart_1_1WAxis.html#a71928aabf753854274d753e266aabfc2">WAxis::setLabelTransform()</a>
	  as a simpler method to change the tick
	  labels depending on the side the axis is drawn on.</li>
      <li><a href="classWt_1_1Chart_1_1WDataSeries.html">WDataSeries</a> is no longer a simple value class. The interface of
          <a href="classWt_1_1Chart_1_1WCartesianChart.html">WCartesianChart</a> has been modified to reflect that: the old
	  interface that copies WDataSeries over has been deprecated in favor of an interface that takes pointers to
	  <a href="classWt_1_1Chart_1_1WDataSeries.html">WDataSeries</a>.</li>
      <li>It's now possible to <a href="classWt_1_1Chart_1_1WDataSeries.html#ae668a1a90ccf668e426fc2d9e370bf2c">specify a different model</a>
      for each <a href="classWt_1_1Chart_1_1WDataSeries.html">WDataSeries</a>.</li>
      <li><a href="classWt_1_1Chart_1_1WPieChart.html#a0ff69f626136fa56e7de27f6a10d770d">Chart::WPieChart::createLabelWidget()</a>
      has been added, making it possible to replace the labels of a
      <a href="classWt_1_1Chart_1_1WPieChart.html">WPieChart</a>
      with widgets.</li>
      <li>Tooltips on charts can now be deferred, which can improve performance of interactive charts, and if you have a lot of tooltips.</li>
    </ul>
  </dd>
</dl>

<hr />

<h2>Release 3.3.5 (Dec 31, 2015)</h2>
<p>
 This release has a focus on bug fixes but also one or two new features:
</p>

<dl>
  <dt>
    <a href="classWt_1_1Chart_1_1WCartesianChart.html">Chart::WCartesianChart</a>
  </dt>
  <dd>
	WCartesianChart has several new features that allow interaction with the
	chart without server roundtrips. These features include zoom, pan,
	crosshair and follow curve functionality.

	This is only available if the chart is drawn
	on an HTML canvas. This is the default rendering method on modern browsers.
	
	When enabled, the crosshair will follow mouse movement,
	and show in the top right corner the coordinate
	(according to X axis and the first Y axis)  corresponding to this position.
  </dd>
  <dt>
  <a href="classWt_1_1Chart_1_1WAxisSliderWidget.html">Chart::WAxisSliderWidget</a>
  </dt>
  <dd>
	WAxisSliderWidget lets you easily focus on a particular range by selecting an XAxis. It will create a sliding widget where you can change the size of the focused region by dragging the blue handles, and change the position by dragging the selected area. When using touch, the size of this area can also be changed using a pinch movement.
  </dd>
  <dt>
  <a href="classWt_1_1WPainter.html">WPainter</a>, <a href="classWt_1_1WJavaScriptHandle.html">WJavascriptHandle</a>, <a href="classWt_1_1WCanvasPaintDevice.html">WCanvasPaintDevice</a>
  </dt>
  <dd>
  The above functionality was implemented by making client-side interaction possible for a scene rendered
  on WCanvasPaintDevice. For this purpose, for several primitives used to draw on a canvas, we provide
  a JavaScript handle and complementary API to manipulate these objects in JavaScript code. In this way you
  can keep the bulk of the painting code in C++, and allow manipulation from within JavaScript.
  Such JavaScript handlers have been made available for <a href="classWt_1_1WTransform.html">WTransform</a>, <a href="classWt_1_1WPen.html">WPen</a>, <a href="classWt_1_1WBrush.html">WBrush</a>, <a href="classWt_1_1WPointF.html">WPointF</a>, <a href="classWt_1_1WRectF.html">WRectF</a> and <a href="classWt_1_1WPainterPath.html">WPainterPath</a>.
  </dd>

  <dt> <a href="classWt_1_1WAnchor.html">WAnchor</a> target (such as this window, or new window) moved to <a href="classWt_1_1WLink.html#afda591cd277562d5c8ea723733290790">WLink</a></dt>
  <dd>As WLink is used in several places (including for example inside item data models), the target can now be specified in more places in the same consisten way. However, since until now a WAnchor was the owner of the TargetType, this may break existing code which calls WAnchor::setTarget() before WAnchor::setLink(), as the latter overrides the target.
  </dd>

  <dt>A new <a href="namespaceWt.html#a6c93a6e97016801a310275457e43f333">TargetDownload</a> target was added for links.</dt>
  <dd>Until now it was recommended to use TargetNewWindow as otherwise this would interfere with the rendering of the current page (since browsers are unaware of the content-type and content-disposition of the target link until after it unloaded the current page. The new TargetDownload option is implemented using the new HTML5 download attribute or, if not supported, by targetting a hidden iFrame contained in the page.
  </dd>

  <dt>The included SQLite version was updated</dt>
  <dd>
  The SQLite version bundled with Wt::Dbo has been updated to version 3.8.10.1. The changelog can be found <a href="https://www.sqlite.org/news.html">here</a>
  </dd>

  <dt>Support for seconds editing in <a href="classWt_1_1WTimePicker.html#a4d19d3ad8bdf0a9a3e35d84f3d298994">WTimePicker</a></dt>
  <dd>WTimePicker was missing the seconds, we've also added the setSecondStep() method.
  </dd>

  <dt><a href="classWt_1_1WCheckBox.html#a2d741874682e9a683d40527b03615d32">WCheckBox::setPartialStateSelectable()</a></dt>
  <dd>Before it was only possible to set the partial state of the WCheckbox when creating the Widget.
  We've added a method WCheckBox::setPartialStateSelectable(bool) which will allow the user to select indeterminate state. This is false by default;
  </dd>

  <dt>New client side connection monitor</dt>
  <dd>The <a href="classWt_1_1WApplication.html#ab6ae1117e316f1a7b31449aaeb83c9cf">WApplication::setConnectionMonitor()</a> method will let the user register a Javascript object that will be notified on connection changes (connection, disconnection, websockets enabled/disabled..)
  The monitor will trigger the onChange method of the provided Javascript object</dd>

  <dt>Support for custom HTML tags for a widgets</dt>
  <dd>We've added <a href="classWt_1_1WWebWidget.html#adf6034e0e715138cae479eae6e324ce6">WWebWidget::setHtmlTagName()</a> that will change the current html tag instead of using the one chosen by Wt by default. This allows the user to create widgets that are not provided by Wt, such as for example semantic tags.
  </dd>

  <dt>Wt::Dbo: allow to forward declare related classes</dt>
  <dd>It is now possible to forward declare all classes that are being referenced in a <a href="group__dbo.html#gaa3de862f9544c4d30b8cbcac4b50feba">belongsTo()</a>, <a href="group__dbo.html#ga00a060d5f4764f673948989f21837548">hasOne()</a> or <a href="group__dbo.html#ga570b71f937c991b000b9db01b327a363">hasMany()</a> relation, helping to reduce the compile time pain of Wt::Dbo.</dd>
</dl>

<hr>

<h2>Release 3.3.4 (Mar 25, 2015)</h2>

<p>
 This release has a focus on bug fixes but also one or two new features,
 of which the following are the most notable:
</p>

<dl>
  <dt>
    Support for dedicated session processes with wthttp connector.
  </dt>
  <dd>
    Until now, only the FastCGI connector allowed the use of dedicated
    processes for individual sessions, by spawning a new process for
    each new session. This functionality has also been added to the
    wthttp connector. In this implementation, the manager process will
    act as a reverse proxy to the dedicated session processes.

    This has as major benefit that there is no longer a choice between
    dedicated session processes on the one hand (supported by FastCGI)
    and support for WebSockets on the other hand (supported by the
    built-in httpd). In fact, there remains little reason to prefer
    FastCGI over the built-in httpd: in those situations where you
    want a proper http server as a front-end, you can still use
    HAproxy or NGINX (or Apache, if you must) as a reverse proxy to
    wthttp.
  </dd>

  <dt>
    <a href="classWt_1_1WIdentityProxyModel.html">WIdentityProxyModel</a>
  </dt>
  <dd>
    This new proxy model simply forwards the structure of the source
    model, without any transformation, and can be used for
    implementing proxy models that reimplement data(), but retain all
    other characteristics of the source model.
  </dd>

  <dt>
    <a href="classWt_1_1Chart_1_1WAbstractChart.html#ac895fb1d1437f51629b49246eda66e3d">Chart::WAbstractChart::setAutoLayoutEnabled()</a>
  </dt>
  <dd>
    Until now, you were responsible for configuring the padding around
    the chart area to accomodate for axis labels, titles, and
    legend. While this is still the default behaviour, we added an
    option to let the chart derive the required padding (using
    approximate font-metrics available server-side).
  </dd>


  <dt>
    <a href="classWt_1_1Chart_1_1WCartesianChart.html#a1c97590b1bd4ee9324822967d6e72333">Chart::WCartesianChart::setAxis()</a>
  </dt>
  <dd>
    Whereas previously a chart axis was a "value class", it is now a
    proper polyymorphic class, and you can provide your own
    implementation. In this way you can customize things like for
    example label strings.
  </dd>  

  <dt>
    Several new features in the 3D charts library.
  </dt>
  <dd>
    <ul>
      <li><a href="classWt_1_1Chart_1_1WAbstractDataSeries3D.html#a0ac582c98fe58f36e0d60f11b5627656">
	  setPointSprite()</a>: ability to define sprites for drawing
	  a data series</li>
      <li><a href="classWt_1_1Chart_1_1WAbstractGridData.html#a8f99da2ab56c80de400c90992c35f882">pickSurface()</a>:
	find out which points on a surface are under a given pixel</li>
      <li><a href="classWt_1_1Chart_1_1WAbstractGridData.html#afc0509b2dff1fa8dbb970266de21f7db">pickBar()</a>:
	find out which points on a bar on are under a given pixel.</li>
      <li><a href="classWt_1_1Chart_1_1WAbstractGridData.html#a09c065c802ff9b21d3c2a543e48f58b2">
	  setIsoLevels()</a>:
	draw iso lines (on the ground plane of the chart) corresponding
	to selected z values.</li>
      <li><a href="classWt_1_1Chart_1_1WAbstractGridData.html#ad74945761f9bfcc2ced42487468c5480">
	  setClippingLinesEnabled()</a>:
	ability to clip and optionally draw clipping planes
      </li>
      <li>
	<a href="classWt_1_1Chart_1_1WCartesian3DChart.html#a8adb0ca981382e3e1435fe8e7fcf1d6e">
	  setIntersectionsEnabled()</a>:
	ability to draw surface-surface intersection lines.
      </li>
    </ul>
  </dd>
</dl>

<hr>

<h2>Release 3.3.3 (May 27, 2014)</h2>

<p>
 This release has a focus on bug fixes but also one or two new features:
</p>

<dl>
  <dt>
    Improved Meta header support.
  </dt>
  <dd>
    Because WApplication meta header API was restricted to only work
    in certain circumstances, we have now added the ability to define
    meta headers (with the option to apply them to specific user agents)
    also in the configuration file.
  </dd>

  <dt>
    <a href="classWt_1_1WWidget.html#ab4086c221a56e81dd067be47303b5862">WWidget::setDeferredToolTip()</a>
    </dt>
  <dd>
    This function is an alternative to setToolTip(), useful when a
    tooltip text is not trivial to fetch or create. Using this
    function, the tool tip (HTML) text can now be loaded on-demand
    instead of needing to be preset on (each) widget. This also works
    for tooltips set from a WAbstractItemModel using the
    new <a href="group__modelview.html#ga1d77c4de293aebfacbdde124de06b8b0">ItemHasDeferredTooltip</a>
    item flag.
  </dd>

  <dt>
    <a href="classWt_1_1WLineEdit.html#ae599502e317ed79d5a1a54dae12d3d10">WLineEdit::setInputMask()</a>
    </dt>
  <dd>
    Support for input masks was added, which guides the user to enter
    data in the correct format.
  </dd>
</dl>

<hr>

<h2>Release 3.3.2 (March 12, 2014)</h2>

<p>
 This release has a focus on bug fixes and a few larger new developments.
</p>

<h3>A) New classes:</h3>

<dl>
  <dt>
    <a href="classWt_1_1Chart_1_1WCartesian3DChart.html">3D Charts
    (Chart::WCartesian3DChart, ...)</a>
  </dt>
  <dd>
    A 3D charting library was added, based on
    <a href="classWt_1_1WGLWidget.html">WGLWidget</a>, and integrated
    with the existing 2D charting framework.
  </dd>

  <dt>
    <a href="classWt_1_1Dbo_1_1JsonSerializer.html">Dbo::JsonSerializer</a>
  </dt>
  <dd>
    This is a utility which serializes Dbo objects (including
    relations) to JSon, leveraging the same persist() function used
    for serialization to the database.
  </dd>

</dl>

<h3>B) Main improvements:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WBootstrapTheme.html">WBootstrapTheme</a>
    </dt>
  <dd>
    Support for bootstrap version 3 was added, so now you have the
    choice between botstrap version 2 or 3. Needless to say, you
    should probably target version 3 for new development work if you
    can live with its restricted browser support.
  </dd>

  <dt>
    <a href="classWt_1_1WGLWidget.html">WGLWidget</a>
    </dt>
  <dd>
    Next to the existing client-side WebGL-based implementation, a
    server-side OpenGL-based implementation was added for fallback
    scenarios where WebGL is not available, or when scene complexity
    is so big that a server-side solution is simply better performing
    because of lower bandwidth needed.
  </dd>

  <dt>
    <a href="classWt_1_1WRasterImage.html">WRasterImage</a>
    </dt>
  <dd>
    Next to the GraphicsMagick-based implementation, a skia-based
    implementation has been added (which provides much higher
    performance most notably on Windows platforms).
  </dd>

  <dt>
    <a href="classWt_1_1WString.html">WString</a>
    </dt>
  <dd>
    Until now, Wt defaults to the C++ global locale for conversion
    between a string literal (std::string, const char *) and
    WString. In practice, UTF-8 is an (increasingly) better choice
    since UTF-8 is a pragmatic encoding covering the entire Unicode
    range, and the encoding used by the library throughout. We've now
    added a setDefaultEncoding() function which can be used to
    configure the default encoding as UTF-8.
  </dd>

  <dt>
    wthttp HTTP/WebSockets front-end server
  </dt>
  <dd>
    We've given the http front-end a much needed overhaul, making it
    deal better with long-lived connections typical for WebSockets
    applications, and fix some nasty issues at the same time.
    We also took the opportunity to optimize its performance by
    reducing the number of system calls for writing request
    responses, and by avoiding memory allocations during request parsing.
  </dd>
</dl>

<h3>C) Non-backwards compatible changes</h3>

<dl>
  <dt>
    <a href="classWt_1_1WDatePicker.html">WDatePicker</a>,
    <a href="classWt_1_1WDateEdit.html">WDateEdit</a>
  </dt>
  <dd>
    The date pickers will now default to interpreting a single click
    as a date selection and also closing the calendar.
  </dd>
</dl>
<hr>

<h2>Release 3.3.1 (October, 16 2013)</h2>

<p>
 This release has a focus on bug fixes and other cleanups after the big
 changes that went into 3.3.0.
</p>

<h3>A) New classes:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WLocalDateTime.html">WLocalDateTime</a>
  </dt>
  <dd>
    So far, the library only provided date/time classes that dealt with
    UTC time (or that at least is the intended use). In this release
    we have added functionality to also deal with date's in a specific
    time zone, which includes this new type as well as improvements in
    WDateTime to convert to local date time, and time zone information
    in WEnvironment and WLocale.
  </dd>

</dl>

<h3>B) Main improvements:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WComboBox.html">WComboBox</a>
    </dt>
  <dd>
    The combo box now interprets LevelRole data to display headers
    (using HTML &lt;optgroup&lt; elements). Another improvement is
    that now the combobox saves its single selection while the model
    is updated.
  </dd>

  <dt>
    <a href="classWt_1_1WDialog.html">WDialog</a>
    </dt>
  <dd>
    Modal dialogs can now be created and destroyed in any order
    without confusing the 'silk screen'. We now also consistently
    interpret an enter press in the dialog to invoke the default
    button added to the dialog footer (if there is one).
  </dd>

  <dt>
    <a href="classWt_1_1WMessageBox.html">WMessageBox</a>
    </dt>
  <dd>
    Several improvements include the ability to indicate what buttons
    are the default and escape buttons with setDefaultButton() or
    button->setDefault() and setEscapeButton(), and the (long overdue)
    implementation of icons!
  </dd>

  <dt>
    <a href="classWt_1_1WTextEdit.html">WTextEdit</a>
    </dt>
  <dd>
    We've added support for TinyMCE 4.
  </dd>

  <dt>
    <a href="classWt_1_1Signal.html">Signal</a>
    </dt>
  <dd>
    For boost versions 1.52 or later, we now support the
    Boost.Signals2 library for the signals implementation.
  </dd>

  <dt>
    <a href="namespaceWt_1_1Render.html">Render library</a>
    </dt>
  <dd>
    We've added a CSS style sheet parser which will parse and apply
    style rules in &lt;style&gt; blocks (or loaded through the API),
    and expanded CSS support to much improvemed table rendering
    (including border-collapse border model and repeated table
    headers), relative/absolute positioning, and page-break-before/after
    support.
  </dd>

  <dt>
    <a href="classWt_1_1Auth_1_1AbstractUserDatabase.html">Auth::AbstractUserDatabase</a>
  </dt>
  <dd>
    A setIdentity() method was added to modify an existing identity
    (e.g. username) and updateAuthToken() was added to update an
    existing token (e.g. keeping the expiration time but changing the
    hash).
  </dd>

  <dt>
    <a href="classWt_1_1Dbo_1_1Query.html">Dbo::Query</a>
  </dt>
  <dd>
    Added a reset() function which resets previous bound arguments.
  </dd>

  <dt>
    <a href="classWt_1_1Dbo_1_1QueryModel.html">Dbo::QueryModel</a>
  </dt>
  <dd>
    The model now implements toRawIndex() and fromRawIndex() methods to
    allow selection to persist across layout changes (e.g. resorting).
  </dd>

  <dt>
    <a href="group__json.html">Wt::Json (JSON library)</a>
  </dt>
  <dd>
    We've added serialization functions to complement the parsing API.
  </dd>

  <dt>
    <a href="group__mail.html">Wt::Mail (SMTP library)</a>
  </dt>
  <dd>
    We've added attachment support, and optional indication of the local
    sender date.
  </dd>

</dl>

<h3>C) Non-backwards compatible changes</h3>

<dl>
  <dt>
    <a href="classWt_1_1WDate.html">WDate</a>,
    <a href="classWt_1_1WDateTime.html">WDateTime</a>
    <a href="classWt_1_1WTime.html">WTime</a>
  </dt>
  <dd>
    We've deprecated the exceptions (Invalid[Date][Time]Exception)
    that were thrown by these classes when one attempted to compute or
    use an 'invalid' value. These exceptions are no longer thrown.
    Instead, we now documented what value
    (usually 'null') is returned when one attempts to do operations on
    such a date/time class, which makes the behaviour more consistent
    with how Qt's equivalent classes behave.
  </dd>

  <dt>
    <a href="classWt_1_1WMessageBox.html">WMessageBox</a></dt>
  <dd>
    The buttons() method has been renamed to standardButtons(), and
    buttons() now return the actual list of added buttons.
  </dd>
</dl>
<hr>

<h2>Release 3.3.0 (April, 8 2013)</h2>

<p>
 This release focusses on a reorganization of Wt's theme
 infrastructure, with the objective of
 supporting <a href="http://twitter.github.com/bootstrap/">Twitter's
 Bootstrap CSS framework</a> as a new theme. At the same time we've
 added a number of widgets for which Twitter Bootstrap provides
 styling.
</p>

<p>It is our intention to support the Bootstrap theme (or more
 specifically, the Bootstrap class names) alongside the themes we
 already supported (which are based on our own class names). Ignoring
 what Bootstrap brings, you should be able to upgrade to this release
 without too much trouble, although you may need to adapt some CSS
 stylesheets as we did reorganize a number of things which were
 required for Bootstrap and were a good idea for our own CSS
 stlesheets too.</p>

<h3>A) New classes:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WTheme.html">WTheme</a>,
    <a href="classWt_1_1WCssTheme.html">WCssTheme</a>,
    <a href="classWt_1_1WBootstrapTheme.html">WBootstrapTheme</a>,
  </dt>
  <dd>
    Theme support classes for Wt. The role of a theme is to:
    <ul>
      <li>Load the CSS stylesheets for a new session</li>
      <li>Annotate newly created widgets with appropriate style
      classes</li>
    </ul>
  </dd>

  <dt>
    <a href="classWt_1_1WDateEdit.html">WDateEdit</a>
  </dt>
  <dd>
    Functionally almost the same as a WDatePicker, this class
    specializes WLineEdit and is thus a WFormWidget, making it much
    easier to use in WTemplateFormView.
  </dd>

  <dt>
    <a href="classWt_1_1WLocale.html">WLocale</a>
  </dt>
  <dd>
    This class supports localization for number formatting and
    extends the simple localization support we had in the previous
    versions of Wt (which as only effect had the selection of
    a different language for the resource bundles). It's main
    added value of native C++ support for localization is that it
    also affects client-side handling and parsing of number values,
    i.e. in <a href="classWt_1_1WIntValidator.html">WIntValidator</a> and
    <a href="classWt_1_1WDoubleValidato.htmlr">WDoubleValidator</a>.
  </dd>
  
  <dt>
    <a href="classWt_1_1WNavigationBar.html">WNavigationBar</a>
  </dt>
  <dd>
    A navigation bar styles a menu as a typical top-level bar
    (currently only styled in the Bootstrap Theme).
  </dd>

  <dt>
    <a href="classWt_1_1WPopupWidget.html">WPopupWidget</a>
  </dt>
  <dd>
    A base class to simplify the creation of popup widgets that
    typically assist in editing or provide circumstancial information
    for another widget.
  </dd>

  <dt>
    <a href="classWt_1_1WSplitButton.html">WSplitButton</a>
  </dt>
  <dd>
    A split button, which combines a button and a popup menu
    (currently only styled in the Bootstrap Theme).
  </dd>

  <dt>
    <a href="classWt_1_1WToolBar.html">WToolBar</a>
  </dt>
  <dd>
    A button tool bar (currently only styled in the Bootstrap Theme)
  </dd>

  <dt>
    <a href="classWt_1_1Dbo_1_1backend_1_1MySQL.html">Dbo::MySQL</a>
  </dt>
  <dd>
    A MariaDB/MySQL backend for Wt::Dbo. This is based on the work
    from Paul Harrisson who maintained this backend so far outside the
    Wt distribution. The backend has been designed for MariaDB, but
    should work fine for MySQL as well.
  </dd>  
</dl>

<h3>B) Main improvements:</h3>

<dl>
  <dt>
    <a href="classWt_1_1Mail_1_1Message.html">Mail::Message</a>
  </dt>
  <dd>
    Added API support for additional SMTP headers.
  </dd>

  <dt>
    <a href="classWt_1_1WDatePicker.html">WDatePicker</a>,
    <a href="classWt_1_1WSuggestionPopup.html">WSuggestionPopup</a>
  </dt>
  <dd>
    The setGlobalPopup() functionality has been deprecated and does no
    longer have any effect, since a new improved algorithm is being
    used to anchor the popup to the DOM which no longer requires this
    workaround.
  </dd>

  <dt>
    <a href="classWt_1_1WDialog.html">WDialog</a>
  </dt>
  <dd>
    Addition of a footer() method that returns a container for dialog
    footer elements, typically buttons.
  </dd>

  <dt>
    <a href="classWt_1_1WFormModel.html">WFormModel</a>
  </dt>
  <dd>
    Addition of a validator() function that returns the validator for
    a field set using setValidator(), 
  </dd>

  <dt>
    <a href="classWt_1_1WGLWidget.html">WGLWidget</a>
  </dt>
  <dd>
    Support for binary transfers which avoids serialization and
    deserialization of floats to text.
  </dd>
  
  <dt>
    <a href="classWt_1_1WPushButton.html">WPushButton</a>
  </dt>
  <dd>
    A push button can now act as a toggle button, using setCheckable()
    and related API (currently only styled in the Bootstrap Theme) and
    can be linked to a popup menu using setMenu().
  </dd>

  <dt>
    <a href="classWt_1_1WStackedWidget.html">WStackedWidget</a>
  </dt>
  <dd>
    When switching between current widgets, the stacked widget will
    now record and restore the current scroll position, providing a
    much improved user experience when using the stacked widget for
    the 'main' contents of an application.
  </dd>

  <dt>
    <a href="classWt_1_1WStringListModel.html">WStringListModel</a>
  </dt>
  <dd>
    Full support was added for storing data of all roles, lifting the
    requirement to use another model such as WStandardItemModel for
    simple MVC widgets like WComboBox or WSuggestionPopup simply to be
    able to store UserRole data.
  </dd>

  <dt>
    <a href="classWt_1_1WTemplate.html">WTemplate</a>
  </dt>
  <dd>
    Added a new standard function (Functions::block) which allows the
    definition and use of a macro block inside a placeholder, which is
    in particular useful for forms which have repetitive formatting
    for each field.
  </dd>

  <dt>
    <a href="classWt_1_1WTemplateFormView.html">WTemplateFormView</a>
  </dt>
  <dd>
    Several API improvements: A new setFormWidget() allows the
    definition of the form widget for editing a field which
    is a more useful alternative compared to reimplement
    createFormWidget(). It also allows the optional
    definition of functions to update the view/model values, which
    avoids the need for specializing updateViewField() and
    updateModelField() these latter two functions have been deprecated
    in favour of two new functions updateViewValue() and
    updateModelValue() which only update the value but not other
    aspects such as visibility, validation state, or messages.
  </dd>
  
  <dt>
    Built-in httpd improvements
  </dt>
  <dd>
    A redundant copy operation of the response generated and sent by
    Wt has been removed, using scatter-gather I/O implemented by
    boost::asio instead.
  </dd>
</dl>

<h3>C) Non-backwards compatible changes</h3>

<dl>
  <dt>
    <a href="classWt_1_1WMenuItem.html">WMenuItem</a>
  </dt>
  <dd>
    While in previous version of Wt, this class was only a data class
    that held the information related to an item, in 3.3.0 we modified
    this so that this class represents the widget itself. If you were
    redefining protected methods to customize the widget
    (i.e. createItemWidget() and updateItemWidget()), then this will no
    longer work as expected. The new system should be easier to
    customize (since you can simply specialize WMenuItem itself).
    In addition, we've simplified the rendering of a menu item so that
    a redundant layer of spans (or div's) has been removed. It makes
    the menu more consistent with the way CSS designers expect a menu
    to rendered, and this was done (you can guess the theme of this
    release by now ?) to be compatible with bootstrap's CSS styles.
  </dd>

  <dt>
    <a href="classWt_1_1WApplication.html">WApplication::locale()</a>
  </dt>
  <dd>
    This now returns a WLocale object instead of the string
    designation of the locale (which you can query by calling name())
    on the locale object.
  </dd>

  <dt>
    <a href="classWt_1_1WCalendar.html">WCalendar</a>
  </dt>
  <dd>
    The markup for this class has changed, and thus customized CSS
    will need to be updated.
  </dd>

  <dt>
    <a href="classWt_1_1WMenuItem.html">WPopupMenuItem</a>
  </dt>
  <dd>
    The popup menu item class has been merged with WMenuItem (and
    WPopupMenu is now a specialized WMenu). This should not have
    noticable API changes, except for the changes in markup and CSS
    documented above.
  </dd>
  
  <dt>
    <a href="classWt_1_1WTreeNode.html">WTreeNode</a>,
    <a href="classWt_1_1WTreeTable.html">WTreeTable</a>
    <a href="classWt_1_1WTreeView.html">WTreeView</a>
  </dt>
  <dd>
    The markup for tree rendering has been changed (to using nested
    unordered list instead of nested tables), and thus customized CSS
    will need to be updated. The only API consequence is that
    WTreeNode::labelArea() is no longer returning a WTableCell but
    instead a WContainerWidget.
  </dd>

  <dt>
    <a href="classWt_1_1WTreeView.html">WTreeView</a>,
    <a href="classWt_1_1WTableView.html">WTableView</a>
  </dt>
  <dd>
    Event handling (clicked(), doubleClicked(), ... ) has been
    generalized: events that are not generated on an item (but for
    example in empty space below the items) will now also
    generate these events, but then with an invalid model index.
    You may thus need to adapt current code to check whether the model
    index that is returned is valid.
  </dd>
</dl>
<hr>

<h2>Release 3.2.3 (November, 1 2012)</h2>

<p>
 This release contains mostly bug fixes and one new feature: a payment
 processing API.
</p>

<h3>A) New namespaces:</h3>

<dl>
  <dt>
    <a href="group__payment.html">Wt::Payment (payment handling)</a>
  </dt>
  <dd>
    This namespace contains services and back-end classes for dealing
    with online payment brokers. At the moment there is support for
    PayPal's Express Checkout service.
  </dd>
</dl>

<h3>B) Main improvements:</h3>

<dl>
  <dt>
    Layout improvements.
  </dt>
  <dd>
    <p>
      If you had massive trouble migrating to 3.2.2 because of the
      layout rewrite, then you'll appreciate the efforts we've made to
      make the layout algorithms in 3.2.3 much more robust and
      consistent.
    </p>
  </dd>

  <dt>
    <a href="classWt_1_1Dbo_1_1QueryModel.html">Dbo::QueryModel</a>:
    added a mechanism for stable row data.
  </dt>
  <dd>
    <p>
      A common nuisance when working with the QueryModel (which
      retrieves data from the database as needed), is that concurrent
      database modifications such as insertions of new data, may
      interfere with the model's mapping of rows to objects (this is
      in fact a common problem with most ORM's indeed). This mapping
      may be important, especially when you want to process the user's
      selection of one or more rows selected by the user, in e.g. a
      table view. We've added a mechanism to assure that one can
      request the model for data at a given row, which is guaranteed
      to be the same row that has been previously retrieved, using the
      stableResultRow() method. It works by default for simple queries
      (returning data from one table), but can be easily customized
      for more complex queries.
    </p>
  </dd>

  <dt>
    <a href="namespaceWt_1_1Render.html">Render library:</a>
    improved support for %-based block sizes and table rendering
  </dt>
  <dd>
    <p>
      Support was added for %-based sizes for block widths and table
      cell widths. In addition, table rendering in Wt::Render has been
      improved to support repeating headers (&lt;thead&gt; sections)
      for multi-page tables, and explicit page breaks (using the css
      page-break-after/before properties).
    </p>
  </dd>

</dl>

<h3>C) Non-backwards compatible changes</h3>

<dl>
  <dt>
    <a href="classWt_1_1Dbo_1_1backend_1_1Sqlite3.html">Dbo::backend::Sqlite3</a>
  </dt>

  <dd>
    <p>We've changed the implementation of the storage ISO8601AsText
    format for time stamps (datetime). In the new, corrected,
    implementation, we generate dates using 'T' as the separator
    between date and time (as mandated by ISO8601), while the old
    behaviour used a space ('&nbsp;') instead as the
    separator. Sqlite3 supports either format equally. This may
    however break some applications which use queries for an exact
    date (or a date comparison), as the results may be affected.
    </p>

    <p> The old behaviour is still available as PseudoISO8601AsText,
    which can be configured using
    <tt>connection.setDateTimeStorage(Wt::Dbo::SqlDateTime,
    Wt::Dbo::backend::Sqlite3::PseudoISO8601AsText)</tt>
    </p>
  </dd>
</dl>
<hr>

<h2>Release 3.2.2 (July, 23 2012)</h2>

<p>
 This release contains mostly bug and feature improvements, but
 also a rewrite of the layout managers in Wt (WBoxLayout and
 WGridLayout), and this comes with some changes in (in most cases
 previously undefined) behaviour.
</p>

<h3>A) New classes:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WSslInfo.html">WSslInfo</a>
  </dt>
  <dd>
    Class containing information on a client-side certificate that may
    have been configured for a SSL connection, and which can be used
    for authentication (accessible from
    <a href="classWt_1_1WEnvironment.html">WEnvironment</a>).
  </dd>

  <dt>
    <a href="classWt_1_1Dbo_1_1weak__ptr.html">Wt::Dbo::weak_ptr</a>
  </dt>
  <dd>
    A weak variant of Wt::Dbo::ptr which is used to implement
    One-to-One relations (see also
    <a
    href="group__dbo.html#ga00a060d5f4764f673948989f21837548">Wt::Dbo::hasOne()
    </a>).
  </dd>

</dl>

<h3>B) Main improvements:</h3>

<dl>
  <dt>
    Rewrite of <a href="classWt_1_1WLayout.html">WBoxLayout, WGridLayout</a>
  </dt>
  <dd>
    <p>
    The layout managers have been reimplement, to address various
    issues with the old implementation, including API (in particular the wonked
    side-effects of AlignTop | AlignJustify) inconsistencies and bugs.
    </p>

    <p>The new implementation no longer uses tables when JavaScript
    is available, but instead using JavaScript-based layout with
    absolute positioning. The table-based implementation is still kept
    for plain HTML sessions (and progressive bootstrap). The code now
    uses exactly the same layout logic for both horizontal and
    vertical layout (but giving precedence to horizontal layout) and
    should be much more consistent (and perhaps also more
    performant). However, because of the many complexities and
    problems with the old code (inconsistent behaviour), you may see
    issues while upgrading. Please see the "Non-backwards compatible
    changes" below for hints on how to deal with this.</p>
  </dd>

  <dt>
    <a href="classWt_1_1WAbstractItemView.html">WAbstractItemView</a>
  </dt>
  <dd>
    <p>
    A drag &amp; drop mime-type can now be specified on a per-item
    basis using a new <a
    href="group__modelview.html#ga0ae864e12320f9f89172735e075ed068">ItemDataRole</a>,
    and the mime-type for the entire selection is computed
    from these individual mime-types.
    </p>
  </dd>

  <dt>
    <a href="classWt_1_1WInteractWidget.html">WInteractWidget</a>
  </dt>
  <dd>
    A new method <a href="classWt_1_1WInteractWidget.html#a60423e777cffa89e6d1373fd25754099">setMouseOverDelay()</a> allows to specify a delay for
    generating the mouseWentOver() event.
  </dd>

  <dt>
    <a href="classWt_1_1Auth_1_1AbstractUserDatabase.html">Auth::AbstractUserDatabase</a>
  </dt>
  <dd>
    A new method <a href="classWt_1_1Auth_1_1AbstractUserDatabase.html#a5067e569748cfad8c3356735a33aa10f">deleteUser()</a> was added, which deletes a user and all
    related authentication information.
  </dd>

  <dt>
    <a href="classWt_1_1Chart_1_1WCartesianChart.html">Chart::WCartesianChart</a>
  </dt>
  <dd>
    A new method <a href="classWt_1_1Chart_1_1WCartesianChart.html#aa6c394c4d9a801d088b7b02c3fd66b28">setAxisPadding()</a> was added, which configures the
    amount of adding between the chart area and the axes.
  </dd>

  <dt>
    <a href="classWt_1_1Chart_1_1WDataSeries.html">Chart::WDataSeries</a>
  </dt>
  <dd>
    A new method <a href="classWt_1_1Chart_1_1WDataSeries.html#ab0dbcd9bcbc0f39a042eb36aa930def4">setCustomMarker()</a> was added which allows the use of a
    user-defined path for the markers. A new role
    MarkserScaleFactorRole was added which allows overriding the
    marker size based on item model data.
  </dd>

</dl>

<h3>C) Non-backwards compatible changes</h3>

<dl>
  <dt>
    <a href="classWt_1_1WLayout.html">WBoxLayout, WGridLayout</a>
  </dt>
  <dd>
    While migrating old code to this version, here are some tips:
    <ol>
      <li><p>Alignment flags</p>
      <p>Previously, specifying an alignment for a widget in a
      layout, or for the layout when set to a container, had a double
      meaning. Not only would it implement the given alignment but also
      revert to passively letting HTML layout decide the layout of the
      contents, and adjust the parent (layout respectively container)
      accordingly. This had all kinds of side effects such as not
      propagating the size of layout-size-aware widgets and quirks in
      the vertical alignment.</p>
      <p><a href="classWt_1_1WContainerWidget.html#aff9884c8efdf90974077e96bcb1701db">WContainerWidget::setLayout(layout, alignment)</a> has been
      deprecated and will be removed from a future release. This call
      was almost always used to let the parent container resize to fit
      the size of the contained children, instead of fitting children
      in the parent container. This behaviour is now
      automatically deduced based on an (empty) size of the parent
      container. In case this heuristic does not work, then setting a
      non-0 maximum size on the container using <a href="classWt_1_1WWebWidget.html#a9b83805a5b8090d296ae4b5939fc9d11">setMaximumSize()</a> will
      act as a trigger, with the added benefit that the parent will only
      be allowed to resize up to a specified maximum size.</p>
      <p>An alignment specified in
      <a href="classWt_1_1WBoxLayout.html#a7c1ec58e25d0b7add93f5f4342844db6">W(Box/Grid)Layout::addWidget(widget, stretch, alignment)</a> now
      purely affects the alignment but has no other side effects. The
      perferred and minimum sizes of a child widget or layout is now
      always taken into account.</p>
      </li>
      <li><p>Child item sizes</p>
      <p>The layout algorithm is now implemented entirely in
      JavaScript, and is more gentle when dealing with a combination
      of cells (or columns/rows) that have a stretch factor and others
      that don't. Previously, a minimum (or fixed) size would be used
      to layout items that do not have a stretch factor. This had for
      example as a consequence that a WText would be narrowed down to its
      minimum width by using word wrapping throughout. Now, the
      preferred size is used for a child item, and shrinking to a minimum
      size only if necessary.</p>
      <li><p>Progressive bootstrap</p>
      A layout in the first page of an application rendered using
      progressive bootstrap will no longer fully upgrade to a full
      JavaScript version, but will result in a hybrid (between
      table-based and JavaScript-based). If it doesn't work out as you'ld
      expect, then you should reconsider the use of progressive bootstrap,
      or the use of a layout manager in your first page.
      </li>
    </ol>
  </dd>
</dl>

<hr>

<h2>Release 3.2.1 (March 16, 2012)</h2>

<p>
  This release contains mostly bug and feature improvements.
</p>

<h3>A) New classes:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WFormModel.html">WFormModel</a>
  </dt>
  <dd>
    A model class for forms. These models are used in Wt::Auth as the
    basis for RegistrationModel and AuthModel, and allow a more
    straight-forward customization of the underlying behavior of these
    forms.
  </dd>

  <dt>
    <a href="classWt_1_1WReadOnlyProxyModel.html">WReadOnlyProxyModel</a>
  </dt>
  <dd>
    A proxy model class which allows to share a source model
    read-only between multiple sessions.
  </dd>

  <dt>
    <a href="classWt_1_1WTemplateFormView.html">WTemplateFormView</a>
  </dt>
  <dd>
    A WTemplate-based standard view implementation that works in conjunction
    with WFormModel.
  </dd>

  <dt>
    <a href="classWt_1_1Auth_1_1AuthModel.html">Auth::AuthModel</a>
  </dt>
  <dd>
    A model that implements authentication logic.
  </dd>

  <dt>
    <a href="classWt_1_1Auth_1_1FacebookService.html">Auth::FacebookService</a>
  </dt>
  <dd>
    An OAuth-2.0 based authentication service implementation for
    Facebook.
  </dd>

  <dt>
    <a href="namespaceWt_1_1Utils.html">Wt::Utils</a>
  </dt>
  <dd>
    This namespace contains a number of utility functions that we
    found useful in projects using Wt. They relate mostly to
    lower-level encoding and decoding functions: base64-, hex-, html-,
    and url-encoding/decoding.
  </dd>
</dl>

<h3>B) Main improvements:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WApplication.html">WApplication</a>
  </dt>
  <dd>
    A new method, WApplication::bind(), is useful in combination with
    WServer::post() to avoid posting to a method of a deleted object,
    leveraging the same life-time tracking as with signal connections.
  </dd>

  <dt>
    <a href="namespaceWt_1_1Render.html">Render library</a>
  </dt>
  <dd>
    A large number of performance improvements, especially for table
    layout and rendering.
  </dd>

  <dt>
    <a href="classWt_1_1Chart_1_1WAxis.html">Chart::WAxis</a>
  </dt>
  <dd>
    DateScale and DateTimeScale axes have improved auto-configuration of
    limits and timesteps, now taking into account the resolution.
  </dd>

  <dt>
    <a href="classWt_1_1Dbo_1_1Transaction.html">Dbo::Transaction</a>
  </dt>
  <dd>
    We've modified the default transaction outcome: a transaction will
    now automatically commit(), unless the transaction is being
    destroyed (goes out of scope) because an exception is being
    thrown, in which case the transaction will rollback(). Previously,
    an uncomitted transaction would always rollback() on destruction.
  </dd>

  <dt>
    <a href="classWt_1_1Dbo_1_1ptr.html">Dbo::ptr</a>
  </dt>
  <dd>
    Added a session() method, returning the session with which the
    session has been associated.
  </dd>

  <dt>
    Shipped SHA-1 implementation.
  </dt>
  <dd>
    We now ship a SHA-1 implementation with Wt and this thus relaxes
    the need for OpenSSL to implement WebSockets and
    Auth::SHA1HashFunction.
  </dd>
</dl>

<h3>C) Non-backwards compatible changes</h3>

<dl>
  <dt>
    <a href="classWt_1_1WTextEdit.html">WTextEdit</a>
  </dt>
  <dd>
    Due to backwards incompatiblity of IE9, we now require the latest
    version of TinyMCE (3.5b1 or later).
  </dd>

  <dt>
    <a href="classWt_1_1Auth_1_1AuthWidget.html">Auth::AuthWidget</a>
  </dt>
  <dd>
    A number of API methods that configure and access the configuration
    were moved to the new Auth::AuthModel class which can be accessed from
    the widget using model().
  </dd>

  <dt>
    <a href="classWt_1_1Auth_1_1AbstractPasswordService_1_1AbstractStrengthValidator.html">Auth::AbstractPasswordService::AbstractStrengthValidator</a>
  </dt>
  <dd>
    The API was simplified to be less unorthodox: validate() now
    returns a Result that contains all the information for it.
  </dd>

  <dt>
    <a href="classWt_1_1Http_1_1Client.html">Http::Client</a>
  </dt>
  <dd>
    We've changed the signature of the parseUrl() utility function to
    parse the URL into a URL structure instead of a collection of
    string parameters.
  </dd>
</dl>

<hr>

<h2>Release 3.2.0 (November 29, 2011)</h2>

<p>
  This release contains a number of new modules, as well as the usual
  batch of <a href="http://redmine.emweb.be/versions/show/13">bug
  fixes</a> and small feature improvements.
</p>

<p>
  In this release we also change the WValidator API in a way that it
  is likely to break existing applications.
</p>

<h3>A) New namespaces:</h3>

<dl>
  <dt>
    <a href="group__json.html">Wt::Json (JSON handling)</a>
  </dt>
  <dd>
    This namespace contains classes (Object, Value, Array) which map
    the JSON types in C++. It also contains a parser to deserialize
    JSON. A writer to serialize to JSON hasn't been added yet.
  </dd>

  <dt>
    <a href="group__mail.html">Wt::Mail (SMTP protocol)</a>
  </dt>
  <dd>
    This namespace contains a Client to send mail messages. It is
    currently offering only limited functionality w.r.t. SMTP protocol
    handling, but contains enough functionality to send standards
    compliant plain-text/HTML mails, with full support for unicode.
  </dd>

  <dt>
    <a href="group__auth.html">Wt::Auth (Authentication)</a>
  </dt>
  <dd>
    <div>This namespace contains model and view classes for
      authentication. It implements password authentication using best
      practices, email verifiation, remember-me tokens, and provisions
      support for federated login with an implementation of OAuth 2.0
      for authentication using third party identity providers.</div>

    <div>We expect that the API may still evolve, especially with
      respect to OAuth 2.0 (which is a draft protocol), and its use
      for OpenID Connect, which is the main use case for OAuth within
      the authentication module.</div>
  </dd>
</dl>

<h3>B) New classes:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WException.html">WException</a>
  </dt>
  <dd>
    We have cleaned up the use of exceptions within Wt. We have
    converted numerous cases where an exception used to be thrown to
    error logging, if the exception was thrown to indicate an API
    problem. When the API problem is not resulting in a corrupt state,
    we now log the error instead of terminating the session. All other
    cases now use an exception that implements WException. This does
    not affect situations where a std::exception was advertised in the
    API.
  </dd>

  <dt>
    <a href="classWt_1_1WIOService.html">WIOService</a>
  </dt>
  <dd>
    <div>
      Previously, boost::asio was used only in the built-in httpd as a
      portable asynchronous I/O reactor implementation. We have now
      moved this into the Wt library itself, where it is now used
      instead of a dedicated thread pool for dispatching requests (and
      other server events), and where it is also used for asynchronous
      I/O by e.g. the Http::Client.
    </div>
    <div>
      The WIOService specializes a boost::asio::service, and integrates
      the thread pool that runs the service.
    </div>
  </dd>

  <dt>
    <a href="classWt_1_1WStringStream.html">WStringStream</a>
  </dt>
  <dd>
    This is a utility class that we have used since long in Wt. It is
    a more efficient replacement for std::stringstream, with mostly a
    compatible API (at least for our purposes). For our purposes it is
    typically a factor of two or more faster.
  </dd>

  <dt>
    <a href="classWt_1_1Http_1_1Client.html">Http::Client</a>, 
    <a href="classWt_1_1Http_1_1Message.html">Http::Message</a>
  </dt>
  <dd>
    <div>We have added an implementation of a Http(s) client. The client
    is intended for consuming web services in Wt, and handles GET or
    POST requests. It is not suitable (yet) for large responses, since
    it buffers the entire response internally.</div>
    <div>The client uses asynchronous I/O, using the WIOService that is
    found in the current WServer instance.</div>
  </dd>

  <dt>
    <a href="classWt_1_1Dbo_1_1backend_1_1Firebird.html">Dbo::Firebird</a>
  </dt>
  <dd>
    <div>Lukasz Matuszewski contributed a Firebird backend
    implementation, thanks !</div>
  </dd>
</dl>

<h3>C) Main improvements:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WAbstractItemView.html">WAbstractItemView</a>
  </dt>
  <dd>
    Added a setHeaderWordWrap() method which configures header text
    word wrapping, and changed setHeaderAlignemnt() so that it now
    allows to change both the horizontal and vertical alignment. This
    replaces the previously interwoven API for both features using the
    multiLine parameter in setHeaderHeight(), which has been
    deprecated. The rendering of the header items has been
    reimplemented, simplified, and cleaned up in the process, avoiding
    rendering problems on IE browsers.
  </dd>

  <dt>
    <a href="classWt_1_1WApplication.html">WApplication</a>
  </dt>
  <dd>
    Two new methods, deferRendering() and resumeRendering() can be
    used to defer the rendering phase in response to the current
    event-loop request. This is useful for situations where you are
    waiting for an asynchronous operation to complete, but want to
    handle this synchronously in the user-interface (i.e. blocking the
    interface until the operation completes). While this is not a good
    idea in general, it may be useful if you can guarantee that the
    event will arrive within an acceptible time (e.g. 1 second). This
    effectively stalls the response to the current request, but avoids
    blocking threads in the process.
  </dd>

  <dt>
    <a href="classWt_1_1WDialog.html">WDialog</a>
  </dt>
  <dd>
    Added setClosable(), which adds a close icon into the title bar.
  </dd>

  <dt>
    <a href="classWt_1_1WFormWidget.html">WFormWidget</a>
  </dt>
  <dd>
    We have cleaned up the use of exceptions within Wt. We have
    converted numerous cases where an exception used to be thrown to
    error logging, if the exception was thrown to indicate an API
    problem. When the API problem is not resulting in a corrupt state,
    we now log the error instead of terminating the session. All other
    cases now use an exception that implements WException. This does
    not affect situations where a std::exception was advertised in the
    API.
  </dd>

  <dt>
    <a href="classWt_1_1WLogger.html">WLogger</a>
  </dt>
  <dd>
    <div>
      We have reorganized the logging within Wt. Internally, a number
      of macros are now used for logging, with as default
      implementation our own (simple) logger, but which can be
      redefined to use instead another logging framework of your
      choice, as some have rightfully requested.
    </div>
    <div>
      But we've also improved our logger so that it now can be
      configured to filter only certain information, based on type and
      scope. This is mostly useful for debuggin and development of Wt
      itself, since it allows us to switch on debugging output, in a
      fine-grained way, in a debug build.
    </div>
    <div>Finally, a new global function has been added (Wt::log()) which
      selects an appropriate logger for logging and is more convenient
      than WApplication::log() which required an application instance.
    </div>
  </dd>

  <dt>
    <a href="classWt_1_1WTemplate.html">WTemplate</a>
  </dt>
  <dd>
    <div>Arguments to bound functions are now parsed and passed to
      the resolveString() methods.</div>

    <div>Two new constructs have been added: conditions and
      functions. Conditions allow certain parts of a template to be
      skipped or included based on a bound condition. Functions are
      useful to automatically resolve certain variables, two built-in
      functions are implemented: one to resolve strings in a message
      resource bundle ("tr"), and another to resolve the id of a bound
      widget ("id").
    </div>
  </dd>

  <dt>
    <a href="classWt_1_1Dbo_1_1collection.html">Dbo::collection&lt;T&gt;</a>
  </dt>
  <dd>
    We've added front() methods that return the first element.
  </dd>

  <dt>
    Built-in httpd connector
  </dt>
  <dd>
    We have expanded the WebSockets implementation to cover newer
    versions of the WebSockets protocol (draft): next to 00, we now
    also support 07, 08 and 13 protocols (with draft-17 semantics).
  </dd>

  <dt>
    Configuration
  </dt>
  <dd>
    On UNIX-like platforms, and using the built-in httpd connector,
    SIGHUP is caught in the WServer::waitForShutdown() utility function,
    and the configuration file (wt_config.xml) is reread.
  </dd>

  <dt>
    Several security improvements
  </dt>
  <dd>
    <dl>
      <dt>DoS mitigation</dt>
      <dd>We have added two measures to prevent DoS attacks that try
	to exhaust the server by spawning sessions. This is in
	particular a risk when deploying using the progressive bootstrap
	method, since then a plain HTML session can be spawned with a
	single request.
	<ul>
	  <li>Plain sessions may be limited to constitute only a
	  fraction of the total number of sessions. This is configured
	  using the &lt;plain-ajax-sessions-ratio-limit&gt;
	  configuration option.</li>
	  <li>Ajax sessions need to confirm their "intelligence" by
	  solving a puzzle which requires them to properly parse the
	  (ever-changing) JavaScript and HTML.</li>
	</ul>
      </dd>
      <dt>Compromised session ID risk reduction</dt>
      <dd>
	A compromised session ID no longer can be used to hijack that
	session.
	<ul>
	  <li>A full page refresh (using the session ID to rerender
	    the current application state) is no longer allowed unless
	    both client IP address and user-agent are unchanged. To
	    still enable page refresh in this situation, you may
	    configure the use of a cookie which can be used to confirm
	    the original browser (although that cookie will not be
	    used for session tracking), using the
	    &lt;session-id-cookie&gt; setting.</li>
	  <li>
	    The session ID cannot be used to POST events to an Ajax
	    session, since these require proof of other ever-changing
	    context specific information, notably a pageId and ackId.
	  </li>
	</ul>
      </dd>
    </dl>
  </dd>

</dl>

<h3>D) Non-backwards compatible changes</h3>

<dl>
  <dt>
    Build options
  </dt>
  <dd>The HTTP_WITH_SSL option has been removed, and is now replaced
    by WT_WITH_SSL -- OpenSSL is now a dependency of Wt inherited by
    the httpd.
  </dd>

  <dt>
    <a href="classWt_1_1WValidator.html">WValidator</a>
  </dt>
  <dd>
    We broke the validate() method, to return a new WValidator::Result
    instead of WValidator::State. The main improvement is that the
    validation may also return a text which contains information on
    why validation failed. This makes the API consistent with the
    client-side API, and obviously much more useful. It will break
    existing application that call validate() or have reimplemented
    validate() in a custom validation class.
  </dd>

  <dt>
    <a href="classWt_1_1Test_1_1WTestEnvironment.html">WTestEnvironment</a>
  </dt>
  <dd>
    This class has moved to a pseudo-connector library
    (libwttest). This was needed to be able to use asynchronous I/O
    (such as Http::Client) in test cases, which rely on a WIOService
    fournished by a WServer instance.
  </dd>
</dl>

<hr>

<h2>Release 3.1.11 (September 23, 2011)</h2>

<p>
  This release
  contains <a href="http://redmine.emweb.be/versions/show/12">many
  bug fixes</a> and a few new features.
</p>

<h3>A) New classes:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WLink.html">WLink</a>
  </dt>
  <dd>
    This class unifies the different link types used in Wt, in a
    single value class. Depending on the context, a link may refer to
    a URL, a resource, or an internal path. We've updated the API
    throughout to replace the function overloads for these different
    cases with a single usage of WLink, simplifying the API (but don't
    worry, we left the old methods, albeit depricated).
  </dd>
  <dt>
    <a href="classWt_1_1WMediaPlayer.html">WMediaPlayer</a>
  </dt>
  <dd>
    A media player has been added which provides a unified framework
    for playing audio and video, and which deals with cross-browser
    issues (chosing a suitable implementation per browser). We've also
    renamed WHTML5Audio, WHTML5Video, and WHTML5Media to WAudio,
    WVideo and WAbstractMedia respectively (since well, everything
    will eventually be HTML5, no ?).
  </dd>
</dl>

<h3>B) Main improvements:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WResource.html">WResource</a>,
    <a href="classWt_1_1Http_1_1ResponseContinuation.html">Http::ResponseContinuation</a>
  </dt>
  <dd>
    Currently, you can already stream the output of a big resource in
    little chunks, using a continuation to resume sending the next
    part. We've now added API methods
    (WResourceContinuation::waitForMoreData() and
    WResource::haveMoreData()) to allow a resource to suspend its
    response because it is currently lacking more data, to continue
    later when new data is available (and without tying up a thread).
  </dd>

  <dt>
    <a href="classWt_1_1WDialog.html">WDialog</a>
  </dt>
  <dd>
    Added an option setResizable() which puts a resize handle in the
    bottom right corner.
  </dd>

  <dt>
    <a href="classWt_1_1WPopupMenu.html">WPopupMenu</a>,
    <a href="classWt_1_1WPopupMenuItem.html">WPopupMenuItem</a>
  </dt>
  <dd>
    Added a triggered() signal, and an option to automatically cancel
    the popup menu when the mouse leaves the menu (after a
    delay). We've also added the possibility to link a popup menu item
    with a WLink, and the option to make the item which has a submenu
    item also itself selectable.
  </dd>

  <dt>
    Dbo::Session
  </dt>
  <dd>
    The load() method has an additional, optional parameter, to force
    rereading the copy from the database.
  </dd>

  <dt>
    Dbo::collection&lt;C&gt;
  </dt>
  <dd>
    Added a count() method which uses a query to determine whether the
    collection contains an element.
  </dd>

  <dt>
    Test::WTestEnvironment
  </dt>
  <dd>
    Added dialogExecuted() and popupExecuted() methods which allow to
    interact with a reentrant eventloop from a test plan.
  </dd>
</dl>

<h3>C) Non-backwards compatible changes</h3>

The item data roles InternalPathRole and UrlRole have been removed,
and replaced by a LinkRole (which contains a WLink value instead).

<h3>D) Deprecated API</h3>

With the introduction of WLink, the following API is being deprecated
(although it can be argued that some of these may be kept for
convenience):

<ul>
  <li>
    WAbstractArea::setRef(): use WAbstractArea::setLink() instead.
  </li>
  <li>
    WAbstractArea::ref(): use WAbstractArea::link() instead.
  </li>
  <li>
    WAbstractArea::setResource(): use WAbstractArea::setLink() instead.
  </li>
  <li>
    WAbstractArea::resource(): use WAbstractArea::link() instead.
  </li>
  <li>
    WAnchor::setRef(): use WAnchor::setLink() instead.
  </li>
  <li>
    WAnchor::ref(): use WAnchor::link() instead.
  </li>
  <li>
    WAnchor::setResource(): use WAnchor::setLink() instead.
  </li>
  <li>
    WAnchor::resource(): use WAnchor::link() instead.
  </li>
  <li>
    WAnchor::setRefInternalPath(): use WAnchor::setLink() instead.
  </li>
  <li>
    WImage::setImageRef(): use WImage::setImageLink() instead.
  </li>
  <li>
    WImage::imageRef(): use WImage::imageLink() instead.
  </li>
  <li>
    WImage::setResource(): use WImage::setLink() instead.
  </li>
  <li>
    WImage::resource(): use WImage::link() instead.
  </li>
  <li>
    WStandardItem::setInternalPath(): use WStandardItem::setLink() instead.
  </li>
  <li>
    WStandardItem::internalPath(): use WStandardItem::link() instead.
  </li>
  <li>
    WStandardItem::setUrl(): use WStandardItem::setLink() instead.
  </li>
  <li>
    WStandardItem::url(): use WStandardItem::link() instead.
  </li>
</ul>

The following classes have been renamed, and the old name is being
deprecated:

<ul>
  <li>
    WHTMLMedia is now WAbstractMedia.
  </li>
  <li>
    WHTMLVideo is now WVideo
  </li>
  <li>
    WHTMLAudio is now WAudio
  </li>
</ul>    

<hr>

<h2>Release 3.1.10 (July 8, 2011)</h2>

<p>
  This release contains a mix of new features and bug fixes 
</p>

<h3>A) New classes:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WAnimation.html">WAnimation</a>
  </dt>
  <dd>
    We have added support for animations to show or hide widgets (used
    in <a href="classWt_1_1WWidget.html#a66bdda41220267a8c7ff9865996e2675">WWidget::setHidden()</a>,
    and <a href="classWt_1_1WStackedWidget.html">WStackedWidget</a>). These
    animations will only be used when the browser supports CSS3
    animations (at the moment of writing that includes latest Firefox,
    Chrome and Safari releases).
  </dd>
  <dt>
    <a href="classWt_1_1WStreamResource.html">WStreamResource</a>
  </dt>
  <dd>
    Dmitriy Igrishin factored this out of the WFileResource since most
    of its functionality (continuations, range support) could be
    generalized to streaming from a std::istream.
  </dd>
</dl>

<h3>B) Main improvements:</h3>

<dl>
  <dt>
    Allowing multiple WServer instances.
  </dt>
  <dd>
    Apparently for no good reasons at all, some singletons were still
    around which prevented you from instantiating
    multiple <a href="classWt_1_1WServer">application servers</a>. Now
    you can (but only using the built-in httpd) instantiate multiple
    servers side by side in the same process, which may server the
    same or different web applications over different ports. A feature
    example (<tt>multiple_servers</tt>) shows how that works.
  </dd>

  <dt>
    Internal path encoding in WTemplate and WText</a>
  </dt>
  <dd>
    <div>
      The
      new <a href="classWt_1_1WTemplate.html#aeee888e560c519ac0e33bfc1ebb315e2">setInternalPathEncoding()</a>
      method will, if needed, enable reencoding of &lt;a&gt; anchors
      which reference internal paths consistent with how in the
      current session internal paths need to be dealt with (which
      depends on whether the browser supports Ajax and HTML5 History).
    </div>
    <div>
      Since this requires an additional XML parsing step (but the
      rapidxml parser that is used is ... rapid !), it is off by
      default.
    </div>
  </dd>

  <dt>
    <a href="classWt_1_1WWApplication.html">WApplication::findWidget()</a>
  </dt>
  <dd>
    Like WWidget::findWidget(), but on the whole application,
    including widgets outside the WApplication::root().
  </dd>

  <dt>
    <a href="classWt_1_1WWApplication.html">WApplication::changeSessionId()</a>
  </dt>
  <dd>
    Generates a new session ID for the application. This is useful to prevent
    session fixation attacks by changing the session ID when a user has
    authenticated successfully.
  </dd>

  <dt>
    <a href="classWt_1_1WResource.html">WResource::setDispositionType()</a>
  </dt>
  <dd>
    This method allows to specify how the browser should preferably
    show a (non-HTML) resource.
  </dd>

  <dt>
    <a href="classWt_1_1WTable.html">WTable</a>
  </dt>
  <dd>
    Methods were added
    to <a href="classWt_1_1WTable.html#a239d85781509ff321eb964af042bcf57">move
    a row</a>
    or <a href="classWt_1_1WTable.html#a0670b90a05a6c0176c773bf8766a5bf2">a
    column</a>. In addition we added methods
    to <a href="classWt_1_1WTableRow.html">WTableRow</a>
    and <a href="classWt_1_1WTableColumn.html">WTableColumn</a> for
    accessing cells in the given row or column.
  </dd>

  <dt>
    <a href="classWt_1_1WTextEdit.html">WTextEdit</a>
  </dt>
  <dd>
    Various improvements to allow more flexible access to TinyMCE
    settings on a per-instance basis.
  </dd>

  <dt>
    <a href="classWt_1_1WWidget.html">WWidget::setToolTip()</a>
  </dt>
  <dd>
    An additional argument was added which may specify the use of
    XHTML tooltips, which are implemented using a &lt;div&gt;.
  </dd>

  <dt>
    Dbo::collection&lt;T&gt;
  </dt>
  <dd>
    Make insert() and erase() also work for a collection involved in a
    1-N relation
  </dd>

  <dt>
    Dbo::ptr&lt;C&gt;
  </dt>
  <dd>
    Improved modify() behaviour returns a proxy object which marks the
    the object dirty also from its destructor, avoiding situations where
    the transaction is flushed during a modification and remainig changes
    are forgotten.
  </dd>

  <dt>
    Dbo::Dbo&lt;C&gt;
  </dt>
  <dd>
    Added setDirty() and self() methods.
  </dd>

  <dt>
    Dbo::backend::Sqlite3
  </dt>
  <dd>
    The packaged sqlite3 version was bumped from 3.6.20 to 3.7.6
  </dd>

</dl>

<h3>C) Non-backwwards compatible changes</h3>

<dl>
  <dt>The signature of the virtual method WWidget::setHidden() has changed.</dt>
  <dd>
    Probably the biggest breaking change since long, this was needed
    to add support for animations. This will break existing code which
    specializes the WWidget::setHidden() method. This code should be
    updated to pass the WAnimation object.
  </dd>
</dl>

<hr>

<h2>Release 3.1.9 (April 7, 2011)</h2>

<p>
  This release contains mostly bug fixes and quality improvements.
</p>

<h3>A) New classes:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WAbstractSpinBox.html">WAbstractSpinBox</a>,
    <a href="classWt_1_1WDoubleSpinBox.html">WDoubleSpinBox</a>
  </dt>
  <dd>
    Refactored and reimplemented the spinbox control into an integer
    and floating point version, which may be implemented either using
    a native HTML5 element or a portable Wt implementation.
  </dd>

</dl>

<h3>B) Main new features in existing classes:</h3>

<dl>
  <dt>
    Internal path handling: HTML5 History API
  </dt>
  <dd>
    <div>
      When the browser supports the HTML5 History API, URLs are now the
      same for plain HTML and Ajax-enabled session (i.e. without the '#'
      trick). This can improve load time and improves the
      user-experience.
    </div>

    <div>
      To avoid problems of resolving resources with relative URLs, a
      new property 'baseURL' can be used (that can be configured in
      wt_config.xml), which allows all relative URLs be resolved from
      the same location.
    </div>
  </dd>

  <dt>
    Internal path handling: no ugly internal paths ('?_=/path')
  </dt>
  <dd>
    The configuration option (--docroot) for the built-in
    httpd allows to specify folders with static paths and when doing
    so, all other requests are forwarded to the application, which in
    turn does no longer need to rely on the ugly '?_=' query parameter
    to encode its internal paths.
  </dd>

  <dt>
    <a href="classWt_1_1WPdfImage.html">WPdfImage</a>, <a href="classWt_1_1WRasterImage.html">WRasterImage</a>
  </dt>
  <dd>
    Improved font support: the library can be optionally built to use
    libpango for resolving characters to glyphs. This allows text to
    be rendered using a mix of different fonts that all provide only
    partial coverage for the entire unicode range. Note that for
    WPdfImage, this currently requires use of a libharu fork
    (https://github.com/kdeforche/libharu/tree/)
  </dd>

  <dt>
    <a href="classWt_1_1WAbstractItemView.html">WAbstractItemView</a>,
    WTableView and WTreeView
  </dt>
  <dd>
    Implementation of setRowHeaderCount() which fixes the number of
    columns that are used as row headers and remain fixed while
    scrolling horiziontally through the table. This replaces the now
    deprecated setColumn1Fixed() API.
  </dd>

  <dt>
    <a href="classWt_1_1WRasterImage.html">WRasterImage</a>
  </dt>
  <dd>
    Several quality improvements: correct rendering of alpha
    compositing, text rendering by libpango, 
  </dd>

  <dt>
    <a href="classWt_1_1WSlider.html">WSlider</a>
  </dt>
  <dd>
    The slider has been reimplemented to allow for using either the
    native HTML5 slider control, or the Wt implementation. The Wt
    implementation can now also be styled through CSS.
  </dd>

  <dt>
    <a href="classWt_1_1WServer.html#abca6890dab44d87bd3af64705ac072d3">WRun()</a>,
    <a href="classWt_1_1WServer.html#a84f84652ccb139850adcf5ea75f50fa5">WServer::addEntryPoint()</a>
  </dt>
  <dd>
    The callback function is now a boost::function<> object, allowing
    you to bind other variables into the callback function.
  </dd>

  <dt>
    <a href="classWt_1_1WServer.html#a2894484a9661d728dc9aa60ba79bb570">WServer::post()</a>
  </dt>
  <dd>
    A safe method to post events to a session, and a useful
    alternative to WApplication::UpdateLock. The simplechat and
    codeview examples were converted to illustrate this method rather
    than the (dead-lock prone) WApplication::UpdateLock approach.
  </dd>

  <dt>
    <a href="classWt_1_1WString.html#abcff7d3d30972762bd5d9279dc903a36">WString::trn()</a>
  </dt>
  <dd>
    Implementation of plural string resolution, with locale-dependent
    rules. The implementation provided
    by <a href="classWt_1_1WMessageResourceBundle.html">WMessageResourceBundle</a>
    allows the same kind of expressions as GNU ngettext().
  </dd>

  <dt>
    <a href="classWt_1_1Chart_1_1WAxis.html#ab36cb584a0aa8bdcc1c3212a9304e6cd">Chart::WAxis::setResolution()</a>
  </dt>
  <dd>
    Allows to specify the minimum chart axis resolution (contributed by Gaetano Mendola).
  </dd>

  <dt>
    <a href="classWt_1_1Dbo_1_1Transaction.html">Dbo::Transaction</a>
  </dt>
  <dd>
    Fixed an issue with internal inconsistencies after transaction rollback.
  </dd>

</dl>

<h3>C) Non-backwwards compatible changes</h3>

<dl>
  <dt>Changed i18n keys for <tt>Wt.WDate.Mon-Sun</tt>
  and <tt>Wt.Date.Jan-Dec</tt></dt>
  <dd>
    We were pointed out the fact that the built-in i18n keys for WDate
    month names had a collision for the month 'May', which had the
    same key for the abbreviated 3-letter variant as the full length
    variant. Therefore in this release we reformatted the abbreviated
    3-letter variant keys to <tt>Wt.WDate.3.Mon-Sun</tt>
    and <tt>Wt.WDate.3.Jan-Dec</tt>. You will need to update your own
    languages copies of these (or better, contribute them and we'll
    maintain them for you!).
  </dd>
</dl>

<h3>D) Android and iPad/iPhone targets</h3>

<p>This release contains initial work on supporting Android and
iPad/iPhone as targets for deploying Wt applications within a webkit
view widget.</p>

<p>For iPad/iPhone, we added a script that builds Wt as an OSX Framework
which may be used in XCode to build iOS applications.</p>

<p>For Android, we added support for building the library and examples as
shared objects which are packaged together with a small Java project
which instantiates a WebView, into standalone APK files.</p>

<p>This is ongoing work. We need to improve support in Wt for Mobile
Webkit to make the applications look and behave more as native
applications on these devices.</p>

<hr>

<h2>Release 3.1.8 (Feb 4, 2011)</h2>

<p>
  This release contains mostly bug fixes, quality improvements,
  and a few new features.
</p>

<h3>A) New classes:</h3>

<dl>
  <dt><a href="classWt_1_1WFontMetrics.html">WFontMetrics</a></dt>
  <dd>
    A font metrics class. Font metrics are only available for
    WPdfImage, and an implementation is planned for WRasterImage.
  </dd>
  <dt><a href="classWt_1_1Render_1_1WTextRenderer.html">Render::WTextRenderer</a>, 
  <a href="classWt_1_1Render_1_1WPdfRenderer.html">Render::WPdfRenderer</a></dt>
  <dd>
    A renderer class for a subset of XHTML, useful for e.g.~generating
    PDF reports.
  </dd>

</dl>

<h3>B) Main new features in existing classes:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WAbstractItemView.html#ad11215811b4de66f3d3c4267b694fe38">WAbstractItemView::setHeaderItemDelegate()</a>
  </dt>
  <dd>
    Rendering of header cells is now also delegated and can be customized.
  </dd>

  <dt>
    <a href="classWt_1_1WAbstractItemView.html#a027a8ad4967a0e269bdabbffca15f489">WAbstractItemView::scrollTo()</a>
  </dt>
  <dd>
    Scroll to a particular item.
  </dd>

  <dt>
    <a href="classWt_1_1WApplication.html#a44c5f0398b5539269be3961b26e95b08">WApplication::setLayoutDirection()</a>
  </dt>
  <dd>
    Added support for Right-To-Left (mirrored) layouts, typically used
    with some middle-Eastern languages. In addition to HTML's built-in
    support for RTL directionality, layout managers, tables and MVC
    tree/table views render their columns in the opposite order.
  </dd>

  <dt>
    <a href="classWt_1_1WBoxLayout.html">WBoxLayout, WGridLayout, WBorderLayout</a>
  </dt>
  <dd>
    Empty layout items do longer create padding, and thus padding
    collapses around empty items (both horizontally and vertically).
  </dd>

  <dt>
    <a href="classWt_1_1WEvent.html">WEvent::eventType()</a>
  </dt>
  <dd>
    Information on the event type may be used during WApplication::notify()
    for e.g. detecting user activity.
  </dd>

  <dt>
    <a href="classWt_1_1WGoogleMap.html">WGoogleMap</a>
  </dt>
  <dd>
    Added support for Google API version 3, alongside version 2.
  </dd>

  <dt>
    <a href="classWt_1_1WPdfImage.html">WPdfImage</a>
  </dt>
  <dd>
    Added support true type font loading, a UTF8 patch for libharu is
    pending to enable full unicode support text rendering.
  </dd>

  <dt>
    <a href="classWt_1_1WWidget.html#afc4bfcc92fa39010cac8775f3332dfa5">WWidget::setWidth()</a>,
    <a href="classWt_1_1WWidget.html#a7d82ee32496743fdd28b30461f95d5ec">WWidget::setHeight()</a>
  </dt>
  <dd>
    Convenience methods for resize() for only width or height.
  </dd>

  <dt>
    <a href="classWt_1_1Chart_1_1WCartesianChart.html">Chart::WCartesianChart</a>
  </dt>
  <dd>
    A number of methods to customize the location and look of the legend.
  </dd>

  <dt>
    <a href="classWt_1_1Chart_1_1WDataSeries.html#a9361e12e94699f59090ae8ac3a4921df">Chart::WDataSeries::setXSeriesColumn()</a>
  </dt>
  <dd>
    Allow use of a specific X series for each data series in scatter plots.
  </dd>

  <dt>
    <a href="group__dbo.html#ga0f2f0c37d44f27e151b8f12412240731">Dbo::belongsTo()</a>, <a href="group__dbo.html#ga0d0cbc70dcfebc659ea1662e9327c90c">Dbo::hasMany()</a>
  </dt>
  <dd>
    Support for foreign key constraints (NotNull, OnDeleteCascade, etc...).
  </dd>

  <dt>
    <a href="group__dbo.html#ga0f2f0c37d44f27e151b8f12412240731">Dbo::Session::rereadAll()</a>
  </dt>
  <dd>
    Can be optionally given a single table name to reread (discard) all object
    data from a single class/table.
  </dd>

  <dt>
    <a href="structWt_1_1Dbo_1_1sql__value__traits.html">Dbo::sql_value_traits&lt;bool&gt;, Dbo::sql_value_traits&lt;long&gt;</a>
  </dt>
  <dd>
    Added mappings for C++ <tt>bool</tt> and <tt>long</tt> types.
  </dd>

</dl>

<h3>C) API and other changes:</h3>

<dl>
  <dt>
    CORS (Cross-Origin Resource Sharing)
  </dt>
  <dd>
    A communication method between browser and server is now chosen
    based on the needs (same origin or cross-origin), and based on
    browser support. Cross-Origin requests are now supported for both
    Ajax and WebSockets, and are are chosen if available and needed,
    reverting to dynamic script-tags otherwise.<br/>

    The WApplication::setAjaxMethod() has no effect anymore, and has
    been deprecated.
  </dd>

  <dt>
    Bootstrap process has changed.
  </dt>
  <dd>
    While tracking bootstrapping problems on IE8 (resulting in a blank
    page instead of a shiny app), we not only found a good workaround
    for that, but also found a way to implement the default bootstrap
    mode so that the stylesheets are applied before the application is
    rendered. This solves the annoying flicker you experienced with
    the default bootstrap mode, and also allows us to remove a number
    of workarounds for IE. As a result of various cleanups, more CSS
    stylesheet rules have been pushed out to the external wt.css
    (theme) stylesheet. If you've created your own theme, you will
    need to take note.
  </dd>

  <dt>
    <a href="group__painting.html#gaf67a889bc5e9f8ab3a59fe58b0fa2128">Wt::BrushStyle</a>
  </dt>
  <dd>
     Wt::WBrushstyle has been renamed to Wt::BrushStyle. This makes it
     consistent with the naming conventions of other enums. Sorry, our
     mistake !
  </dd>
</dl>

<hr />

<h2>Release 3.1.7 (Nov 26, 2010)</h2>

<p>
  This release contains mostly bug fixes, quality improvements,
  and a few new features.
</p>

<p>
  Note: the package was updated (3.1.7a) on Nov 30 to fix a layouting
  regression.
</p>

<h3>A) New classes:</h3>

<dl>
  <dt><a href="classWt_1_1WGLWidget.html">WGLWidget</a></dt>
  <dd>
    A preview of WebGL support in Wt (work in progress).
  </dd>
</dl>

<h3>B) Main new features in existing classes:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WAbstractItemView.html#a120156dc59eaf3608916b679d937c5b8">WAbstractItemView</a>
  </dt>
  <dd>Added API for hiding columns.</dd>
  <dt>
    <a
  href="classWt_1_1Chart_1_1WCartesianChart.html">WCartesianChart</a>,
    <a
  href="classWt_1_1Chart_1_1WCartesianChart.html">WPieChart</a>
  </dt>
  <dd>
    Added support for ToolTipRole data, using WAbstractArea interactive areas.
  </dd>
  <dt>
    <a href="classWt_1_1Dbo_1_1Session.html#ad59da4e078a4e6532da698425193bbdb">Dbo::Session::rereadAll()</a>
  </dt>
  <dd>
    Reread all transient objects, as a catch-all solution to stale
    data (data modified in another session).
  </dd>
  <dt>
    <a href="classWt_1_1WInteractWidget.html#ac7d10a6cae1e23a791b44c0682a3c627">WInteractWidget</a>
  </dt>
  <dd>Added support for touch and gesture events (Mobile webkit).</dd>
</dl>

<h3>C) Misc:</h3>

<dl>
  <dt>
    WebSocket protocol support (experimental)
  </dt>
  <dd>Use of WebSocket for communication between browser and server
    can now be used, by enabling &lt;web-sockets&gt; in the
    configuration file (we're likely to turn this on by default in a
    future version. There is automatic fallback to the current
    XMLHttpRequest based communication if WebSockets are not available
    or communication could not be established. WebSockets is only
    available using the built-in httpd server (which is now also a
    WebSocket server).</dd>
  <dt>
    Build improvements
  </dt>
  <dd>
    <ul>
      <li>Provide a workaround for broken g++ compiler shipped in Ubuntu
      Maverick</li>
      <li>Provide support for building without using 
      std::wstring (-DWT_NO_STD_WSTRING) or std::locale
      (-DWT_NO_STD_LOCALE=OFF) support.
      </li>
    </ul>
  </dd>
</dl>

<hr />

<h2>Release 3.1.6 (Oct 29, 2010)</h2>

<p>
  This release contains a healthy mix of bug fixes, quality improvements,
  and new features. And hopefully no regressions :-)
</p>

<h3>A) New classes:</h3>

<dl>
  <dt><a href="classWt_1_1SyncLock.html">SyncLock&lt;Lock&gt;</a></dt>
  <dd>
    A dead-lock avoidance adaptor for a Boost mutex lock, which provides
    a controlled way of releasing the current application lock.
  </dd>
  <dt><a href="classWt_1_1WProgressBar.html">WProgressBar</a></dt>
  <dd>
    A progress bar, contributed by Thomas Suckow.
  </dd>
  <dt><a href="classWt_1_1WSpinBox.html">WSpinBox</a></dt>
  <dd>
    A spin box.
  </dd>
  <dt><a href="structWt_1_1boost__any__traits.html">boost_any_traits&lt;Type&gt;</a></dt>
  <dd>
    A traits class for customized interpretation of data stored in a
    boost::any. You can register a new type using <a href="group__modelview.html#ga91842a84102ee15d41102ccf0745f4e4">registerType&lt;Type&gt;</a>.
  </dd>

</dl>

<h3>B) Main new features in existing classes:</h3>

<dl>
  <dt>
    Native support for MSIE 9
  </dt>
  <dd>
    MSIE 9 (Beta) is now supported in all its goodness, including support
    for HTML5 canvas and (almost working) support for SVG.
  </dd>
  <dt>
    <a href="classWt_1_1WApplication_1_1UpdateLock.html">
      WApplication::UpdateLock</a>
  </dt>
  <dd>The lock is now a RIAA lock, getUpdateLock() has been deprecated.
    The lock needs also to be tested against validity (using operator bool()):
    when invalid the session that it is trying to lock is being destroyed.</dd>
  <dt>
    <a href="classWt_1_1WApplication.html#a506978cfb884af4bc6ffd5a5bc8476d6">WApplication::setConfirmCloseMessage()</a>
  </dt>
  <dd>Provide the user with a message to confirm navigating away from the
    application.</dd>
  <dt>
    <a href="classWt_1_1WApplication.html#a9a4048e01b69a536e35f47eb2a59a69b">WApplication::unload()</a>
  </dt>
  <dd>Rather then waiting for the session to expire, an application
    that is navigated away iis now notified of this and will by
    default <tt>quit()</tt>.</dd>
  <dt>
    <a href="classWt_1_1WApplication.html#a149412d829d104621c445bc10604be53">WApplication::addMetaHeader()</a>
  </dt>
  <dd>Can now be used to specify "http-equiv" meta headers too.</dd>
  <dt>
    <a href="classWt_1_1WDatePicker.html#acda30d9035692895a2bb94090babc073">WDatePicker::changed()</a>
  </dt>
  <dd>I wonder how we ever did without.
  </dd>
  <dt><a href="classWt_1_1WAbstractArea.html#a3dbe39c26769a63e4bf63020e31e9f22">WAbstractArea::mouseWheel()</a>,
  <a href="classWt_1_1WInteractWidget.html#a656a0e4d5af72af0190d84dedf0093c6">WInteractWidget::mouseWheel()</a>,
  <a href="classWt_1_1WMouseEvent.html#a4354738e0bce7e57764a465f5e19895d">WMouseEvent::wheelDelta()</a></dt>
  <dd>
    Added mouseWheel() event.
  </dd>

  <dt><a href="classWt_1_1WFileUpload.html">WFileUpload</a></dt>
  <dd>
    Added support for the simultaneous upload of multiple files (HTML5
    "multiple") attribute and showing a progress bar to show upload
    progress.
  </dd>

  <dt><a href="classWt_1_1WFormWidget.html">WFormWidget::hasFocus()</a></dt>
  <dd>
    Returns whether the widget currently has the keyboard focus.
  </dd>

  <dt><a href="classWt_1_1WHTML5Media.html">WHTML5Media</a></dt>
  <dd>
    Added events to catch play, pause, play-back progress and volume
    changes.
  </dd>

  <dt><a href="classWt_1_1WLineEdit.html">WLineEdit</a>, <a href="classWt_1_1WTextArea.html">WTextArea</a></dt>
  <dd>
    Added <tt>currentPosition()</tt>, <tt>selectionStart()</tt>,
    <tt>selectedText()</tt>, and <tt>hasSelectedText()</tt> methods to retrieve
    the current cursor position and selection.
  </dd>

  <dt><a href="classWt_1_1WPushButton.html#aa5830a2118836423f0c16d12bbfd57a0">WPushButton::setRef()</a></dt>
  <dd>
    Utility method to create an anchor that looks like a button, or a
    button that behaves like an anchor, depending on your point of
    view. There is also <tt>setResource()</tt> to set a resource as
    target.
  </dd>
  <dt>
    <a href="classWt_1_1WResource.html">WResource</a>
  </dt>
  <dd>Added API for upload progress tracking.</dd>

  <dt>
    <a href="classWt_1_1Http_1_1Request.html">Http::Request</a>
  </dt>
  <dd>Added support for HTTP request byte ranges, and this is now
  interpreted by both the WFileResource and built-in httpd for static
  files.
  </dd>
  <dt>
    <a href="classWt_1_1Http_1_1Response.html">Http::Response</a>
  </dt>
  <dd>Added <tt>setContentLength()</tt> which allows you to specify the
    lenght of the response in advance, proving a better user experience
    for large downloads.
  </dd>
  <dt>
    <a href="classWt_1_1Dbo_1_1Session.html#8712ff0d59f7bb6a4d2986ad9637cc9e">Dbo::Session::query()</a>
  </dt>
  <dd>Switched to a more complete Boost.Spirit parser for SQL queries, which
    understands most of the SQL syntax, including functions,
    "with ... select ... ".
  </dd>
  <dt>
    <a href="classWt_1_1Dbo_1_1QueryModel.html">Dbo::QueryModel</a>
  </dt>
  <dd>Added support for custom column header names and changing the
    undelrying query using setQuery() while preserving the current
    column definitions.</dd>
  <dt>
    <a href="classWt_1_1Dbo_1_1SqlStatement.html">Dbo::SqlStatement</a>
  </dt>
  <dd>Added boost::posix_time::time_duration type support.</dd>
  <dt>
    <a href="structWt_1_1Dbo_1_1sql__value__traits.html">Dbo::sql_value_traits&lt;WTime&gt;</a>
  </dt>
  <dd>Added template specialization for WTime.</dd>
</dl>

<hr />

<h2>Release 3.1.5 (Sep 10, 2010)</h2>

<p>
  This release contains mostly bug fixes.
</p>

<h3>A) Main Changes</h3>

<dl>
  <dt><a href="classWt_1_1WGridLayout.html">WGridLayout</a>,
    <a href="classWt_1_1WBoxLayout.html">WBoxLayout</a></dt>
  <dd>Optimized client-side rendering performance. Previously, every layout
    manager used would automatically slowdown every event because it would try
    to relayout each time. This is no longer the case.</dd>
  <dt><a href="classWt_1_1WSocketNotifier.html">WSocketNotifier</a></dt>
  <dd>The socket notifier has been resurrected (it was in an perpetual state
    of brokeness) and now works reliably across targets.</dd>
</dl>

<h3>B) Changes that may break existing applications:</h3>

<h4>1) Built-in resource bundles</h4>

Starting with this version, Wt uses an internal message resource
bundle for the few strings it provides by itself (like for example
'Ok' for the ok button in a WMessageBox, or the days-of-week in WDate).

Previously, an ugly API was used in <a href="classWt_1_1WMessageBox.html">WMessageBox</a>,
<a href="classWt_1_1WCalendar.html">WCalendar</a>,
and <a href="classWt_1_1WDatePicker.html">WDatePicker</a>
using a boolean 'i18n' parameter in the constructor. All this has now been removed,
and instead the keys for these built-in strings have been documented. If you were
using these classes your application will no longer build, you can simply remove the
internationalization parameter and you will need to fix the keys you used for the
messages according to the documentation.

Any localized strings you use will take precedence over these built-ins.

All affected classes (only those listed above actually have changed API and behaviour) are:
<dl>
  <dt><a href="classWt_1_1WAbstractItemView.html">WAbstractItemView</a></dt>
  <dd>the paging tool bar buttons for graceful callback.</dd>
  <dt><a href="classWt_1_1WCalendar.html">WCalendar</a></dt>
  <dd>because of WDate</dd>
  <dt><a href="classWt_1_1WDate.html">WDate</a> and <a href="classWt_1_1WDateTime.html">WDateTime</a></dt>
  <dd>week days, month names</dd>
  <dt><a href="classWt_1_1WDatePicker.html">WDatePicker</a></dt>
  <dd>because of WCalendar and for the close button</dd>
  <dt><a href="classWt_1_1WDefaultLoadingIndicator.html">WDefaultLoadingIndicator</a></dt>
  <dd>loading text</dd>
  <dt><a href="classWt_1_1WInPlaceEdit.html">WInPlaceEdit</a></dt>
  <dd>save and cancel button text</dd>
  <dt><a href="classWt_1_1WMessageBox.html">WMessageBox</a></dt>
  <dd>standard buttons</dd>
  <dt><a href="classWt_1_1WOverlayLoadingIndicator.html">WLoadingIndicator</a></dt>
  <dd>standard buttons</dd>
  <dt><a href="classWt_1_1WValidator.html">Validators</a></dt>
  <dd>for the messages they display in case of error</dd>
</dl>

<h4>2) Other behavioural changes</h4>

<dl>
  <dt><a href="structWt_1_1WDialog.html">WDialog</a></dt>
  <dd>Escape will no longer result in the dialog being rejected. You can
    enable this behaviour using the rejectWhenEscaped() method.
  </dd>
</dl>

<hr />

<h2>Release 3.1.4 (Aug 13, 2010)</h2>

<p>
  This release contains several new features, but also a few changes
  that break backwards compatibility (but are unlikely to affect an
  average application).
</p>

<h3>A) New classes:</h3>

<dl>
  <dt><a href="classWt_1_1WBatchEditProxyModel.html">
      WBatchEditProxyModel</a></dt>
  <dd>A proxy model that caches editing operations to commit them atomically.
  </dd>
  <dt><a href="classWt_1_1WHTML5Audio.html">WHTML5Audio</a></dt>
  <dd>Audio support using the HTML5 audio tag.</dd>
  <dt><a href="classWt_1_1WPdfImage.html">WPdfImage</a></dt>
  <dd>A WPaintDevice that writes to Pdf (using libharu).</dd>
  <dt><a href="classWt_1_1WRasterImage.html">WRasterImage</a></dt>
  <dd>A WPaintDevice that writes to a Png/Gif (using GraphicsMagick).</dd>
  <dt>ISAPI connector</dt>
  <dd>(Windows only) a connector that implements the Microsoft ISAPI
    API, to integrate directly into Microsoft IIS. On Windows, this is
    an alternative deployment option next to the built-in httpd.</dd>
</dl>

<h3>B) Main new features in existing classes:</h3>

<dl>
  <dt>
    <a href="classWt_1_1WAbstractItemView.html">WAbstractItemView</a>
  </dt>
  <dd>Added support for validators while editing.</dd>
  <dt>
    <a href="classWt_1_1WApplication.html#88b082dadadd3fb7dbe10887e7d89c91">WApplication</a>
  </dt>
  <dd>Added an appRoot() method this returns the value of the
    special property "approot" which can in some cases be defined
    implicitly by a connector (such as ISAPI), and which allows an
    application to reference working files whereas previously it was
    assumed that they were in the working directory (CWD).</dd>
  <dt>
    <a href="classWt_1_1WEnvironment.html#fd8726dfa8cabcb49895df4a6112ef48">WEnvironment::agent() and related</a>
  </dt>
  <dd>Convenience methods that return pre-parsed user agent identification,
    should you want to differentiate based on browser.</dd>
  <dt>
    <a href="classWt_1_1WWidget.html#bb5949e98f47edb7db98d7b6df07a31c">WWidget::addStyleClass()</a>, <a href="classWt_1_1WWidget.html#3b8a35e37ef06c408f346c63a5f1aa8e">WWidget::removeStyleClass()</a>
  </dt>
  <dd>Added addStyleClass() and removeStyleClass() methods.</dd>
  <dt>
    <a href="classWt_1_1WMenu.html">WMenu, WMenuItem</a>
  </dt>
  <dd>Added support for closable and disabled items (not complete,
    CSS is lacking for polished theme). Contributed by Dmitriy Igrishin.</dd>
  <dt>
    <a href="classWt_1_1WModelIndex.html#93c11e136a0fdc596eb745cc7fce7033">WModelIndex</a>
  </dt>
  <dd>Added support for in-place (destructive) encoding to and
  decoding from a raw index, making this less of a hassle for View
  classes.</dd>
  <dt>
    <a href="classWt_1_1WSortFilterProxyModel.html">WSortFilterProxyModel</a>
  </dt>
  <dd>Added support for row insertion/removal.</dd>
  <dt>
    <a href="classWt_1_1WSuggestionPopup.html">WSuggestionPopup</a>
  </dt>
  <dd>Allow usage as an advanced combo-box, with an explicit drop down
  button and ability to react to a selection.</dd>
  <dt>
    <a href="group__dbo.html#gc98c1f90b00ed9ce243c6412da3ac489">Dbo::id()</a>
  </dt>
  <dd>Support for natural keys (possibly of composite type) next to the
    built-in surrogate keys.</dd>
  <dt>
    <a href="structWt_1_1Dbo_1_1dbo__traits.html">Dbo::dbo_traits&lt;C&gt;</a>
  </dt>
  <dd>By specializing this traits class, you can modify the surrogate id
    field name (or disable it), and the optimistic version lock field
    name (or disable it).</dd>
  <dt>
    <a href="classWt_1_1Dbo_1_1Session.html#8712ff0d59f7bb6a4d2986ad9637cc9e">Dbo::Session::query()</a>
  </dt>
  <dd>More robust query parsing (of the 'select' part), including
  support for "select distinct".</dd>
  <dt>
    <a href="classWt_1_1Dbo_1_1QueryModel.html">Dbo::QueryModel</a>
  </dt>
  <dd>Added editing support (editing the model will modify the queried
  dbo's).</dd>
  <dt>
    <a href="structWt_1_1Dbo_1_1query__result__traits.html">Dbo::query_result_traits&lt;C&gt;</a>
  </dt>
  <dd>Added setValue(), create(), add() and remove() methods for modifying
    queried results.</dd>
</dl>

<h3>C) Changes that break existing applications:</h3>

<dl>
  <dt><a href="structWt_1_1Dbo_1_1Dbo.html">Dbo::Dbo</a></dt>
  <dd>
    This class is now a templated with the class name itself, in
    order to provide the proper type for the (natural or surrogate) id
    field for id(). You will need to replace
    <pre>
      class User : public Wt::Dbo { ... }
    </pre>
    with
    <pre>
      class User : public Wt::Dbo&lt;User&gt; { ... }
    </pre>
  </dd>
  <dt>CSS</dt>
  <dd>The toplevel container used by Wt is now given a <tt>position:
    relative</tt> style; this was needed to be able to position widgets
    (such as popups) using <tt>position: absolute</tt>, but may break
    application layouts. You can override this CSS style by adding
    <tt>.Wt-domRoot { position: static; }</tt> to your application's
    (internal or external) stylesheet.
  </dd>
</dl>

<hr />

<h2>Release 3.1.3 (May 20, 2010)</h2>

<p>
  This release several new features, but also a few changes that
  break backwards compatibility (but are unlikely to affect an average
  application).
</p>

<h3>A) New classes:</h3>

<dl>
  <dt><a href="classWt_1_1SignalBase.html">SignalBase</a>,
    <a href="classWt_1_1EventSignalBase.html">EventSignalBase</a></dt>
  <dd>Abstract base classes for signals (these are not actually new,
    but they were not yet part of the API).</dd>
  <dt><a href="classWt_1_1WHTML5Video.html">WHTML5Video</a></dt>
  <dd>Video support using the HTML5 video tag (work-in-progress).</dd>
  <dt><a href="classWt_1_1Dbo_1_1Call.html">Dbo::Call</a></dt>
  <dd>Class for executing a database call.</dd>
  <dt><a href="classWt_1_1Dbo_1_1SqlConnectionPool.html">
      Dbo::SqlConnectionPool</a>,
    <a href="classWt_1_1Dbo_1_1FixedSqlConnectionPool.html">
      Dbo::FixedSqlConnectionPool</a></dt>
  <dd>Connection pool interface and implementation.</dd>
  <dt><a href="classWt_1_1Dbo_1_1QueryModel.html">Dbo::QueryModel</a></dt>
  <dd>An tabular item model for query results.</dd>
</dl>

<h3>B) Main new features in existing classes:</h3>

<dl>
  <dt><a href="classWt_1_1WAbstractItemDelegate.html">WAbstractItemDelegate</a></dt>
  <dd>Added methods for editing: editState(), setEditState(),
    setModelData() and closeEditor().</dd>
  <dt><a href="classWt_1_1WAbstractItemView.html">WAbstractItemView</a></dt>
  <dd><div>New editing API: edit(), closeEditor(), saveEditedValue(),
    setEditOptions(), setEditTriggers().</div>
    <div>Graceful degradation support using a paging navigation bar, which
    may be customized by reimplementing createPageNavigationBar().</div>
  </dd>
  <dt><a href="classWt_1_1WCalendar.html">WCalendar</a>, <a href="classWt_1_1WDatePicker.html">WDatePicker</a></dt>
  <dd>Added setBottom() and setTop() methods to specify a valid range.</dd>
  <dt><a href="classWt_1_1WInteractWidget.html">WInteractWidget</a></dt>
  <dd>Added a mouseDragged() event for responding to mouse moves while
    a mouse button is down.</dd>
  <dt><a href="classWt_1_1WItemDelegate.html">WItemDelegate</a></dt>
  <dd>Implements editing using a WLineEdit.</dd>
  <dt><a href="classWt_1_1WMenu.html">WMenu</a></dt>
  <dd>Can now be used without a contents stack.</dd>
  <dt><a href="classWt_1_1WSuggestionPopup.html">WSuggestionPopup</a></dt>
  <dd>Added API to support dynamic server-side filtering.</dd>
  <dt><a href="classWt_1_1WTableView.html">WTableView</a></dt>
  <dd>New implementation which supports horizontal and vertical
  virtual scrolling, column resizing, drag and drop, etc... like
  WTreeView.</dd>
  <dt><a href="classWt_1_1Chart_1_1WPieChart.html">Chart::WPieChart</a></dt>
  <dd>Supports now also a shadow effect.</dd>
  <dt><a href="classWt_1_1Dbo_1_1collection.html">Dbo::collection</a></dt>
  <dd>A find() method has been added to refine the query of a many-side relational.</dd>
  <dt><a href="classWt_1_1Dbo_1_1ptr.html">Dbo::ptr</a></dt>
  <dd>A version() method returns the current version.</dd>
  <dt><a href="classWt_1_1Dbo_1_1Query.html">Dbo::Query</a></dt>
  <dd>An extra template parameter specifies a binding strategy. The
  default binding strategy is DynamicBinding, which allows reuse of
  the query object, and provides new API to modify the query:
  where(), orderBy(), groupBy(), offset(), limit().</dd>
  <dt><a href="classWt_1_1Dbo_1_1Session.html">Dbo::Session</a></dt>
  <dd>Added support for use with a connection pool. Added execute()
  method to execute an SQL statement.</dd>
  <dt>Built-in httpd</dt>
  <dd>Support for HTTP Range header and partial content servering.</dd>
</dl>

<h3>C) Changes that break existing applications:</h3>

<dl>
  <dt><a href="structWt_1_1Dbo_1_1query__result__traits.html">Dbo::sql_result_traits</a></dt>
  <dd>This traits class has been renamed to query_result_traits and
    its API has changed considerably. This will only impact when you
    have implemented a custom traits specialization. The getColumns()
    method has been replaced with a getFields() method, and the
    loadValues() method has been renamed to load(). A getValues()
    method has been added which provides conversion to boost::any's.
  </dd>
  <dt><a href="classWt_1_1WTableView.html">WTableView</a></dt>
  <dd>This View class was reimplemented to have functionality
    comparable to WTreeView. In the process, we had to abandon the
    underlying &lt;table&gt; representation because of rendering
    issues with Chrome (of all browsers!), although the WTableView
    documentation specifically promised that we would keep this.
  </dd>
</dl>

<hr />

<h2>Release 3.1.2 (March 26, 2010)</h2>

<p>This release contains mostly bug fixes, and a few new features.</p>

<h3>A) New classes:</h3>

<dl>
  <dt><a href="classWt_1_1WShadow.html">WShadow</a></dt>
  <dd>Class representing a drop shadow effect (see below).</dd>
  <dt><a href="classWt_1_1Dbo_1_1backend_1_1Postgres.html">Dbo/backend/Postgres</a></dt>
  <dd>A Postgres backend has landed, contributed by Hilary Cheng.</dd>
</dl>

<h3>B) Main new features in existing classes:</h3>

<dl>
  <dt><a href="classWt_1_1WBoxLayout.html">WBoxLayout</a>, <a href="classWt_1_1WGridLayout.html">WGridLayout</a></dt>
  <dd>Addition of horizontal and vertical splitter support (resize handles to
    allow the user to adjust the layout), sponsored by Eurofer. The new API
    methods are <a href="classWt_1_1WBoxLayout.html#00bdfb4d442bd8e8ad9c33b72692763f">setResizable()</a>, <a href="classWt_1_1WGridLayout.html#180c33a8f9e21a7b58f12e055fdb469e">setColumnResizable()</a> and <a href="classWt_1_1WGridLayout.html#6028853eb5a66d868323d0e034b69390">setRowResizable()</a></dd>
  <dt><a href="classWt_1_1WCalendar.html">WCalendar</a></dt>
  <dd>Improved the API to allow custom cell rendering, and custom handling
    of selection. We have also made the API for selection consistent with other
    widgets (like WTreeView), deprecating the old API.</dd>
  <dt><a href="classWt_1_1WDateTime.html">WDateTime</a></dt>
  <dd>Added <a href="classWt_1_1WDateTime.html#0d7f04bacc6ea6534bc61ec7305a8262">toPosixTime()</a> and <a href="classWt_1_1WDateTime.html#eb5f093554829688b36640f0977da541">fromPosixTime()</a> methods to interoperate with
    <tt>boost::posix_time::ptime</tt>.</dd>
  <dt><a href="classWt_1_1WFormWidget.html">WFormWidget</a></dt>
  <dd>Added a <a href="classWt_1_1WFormWidget.html#92de7a4d9ca6796607dc9fd26f608436">setEmptyText()</a> method to implement a label inside a line edit or text area.</dd>
  <dt><a href="classWt_1_1WPainter.html">WPainter</a></dt>
  <dd>Added a <a href="classWt_1_1WPainter.html#9c727b82879ab055f3fcf4c9cdfc1f8d">setShadow()</a> method which defines a drop shadow to be used for subsequent
  drawing actions.</dd>
  <dt><a href="classWt_1_1WResource.html">WResource</a></dt>
  <dd>Added a <a href="classWt_1_1WResource.html#06bb9dbe3ae195c320cfed7b062d448a">setInternalPath()</a> method which allow a resource to be deployed at a deterministic and "pretty" URL.</dd>
  <dt><a href="classWt_1_1WString.html">WString</a></dt>
  <dd>Added constructors that take a std::locale for interpreting a narrow
    string in a given locale.</dd>
  <dt><a href="classWt_1_1WWidget.html">WWidget</a></dt>
  <dd>Added <a href="classWt_1_1WWidget.html#4f83592912a7f8fa4fd35dadde78ee74">setLayoutSizeAware()</a> and <a href="classWt_1_1WWidget.html#f432588db3d599f89b54121f2ede8d63">layoutSizeChanged()</a> methods which allow a widget to react to layout size changes.</dd>
  <dt><a href="classWt_1_1Http_1_1Request.html">Http::Request</a></dt>
  <dd>Added access to the request <a href="classWt_1_1Http_1_1Request.html#e76664f93462d9311ee671c93607e5ca">method()</a>.</dd>
  <dt><a href="classWt_1_1Http_1_1Response.html">Http::Response</a></dt>
  <dd>Added a <a href="classWt_1_1Http_1_1Response.html#7c14ba3ab34ff14461df3a4369118443">setStatus()</a> method to modify the response status.</dd>
  <dt><a href="classWt_1_1Dbo_1_1Session.html">Dbo::Session</a></dt>
  <dd>Added support for schema qualified tables, in
    <a href="classWt_1_1Dbo_1_1Session.html#5886d450c052ae0ee15ab3c91e439229">Session::mapClass()</a> and the joinTable specified in <a href="group__dbo.html#g1a086b583fb150dbd4c5b4ba92bc177f">hasMany()</a>.<br />
    Added API for dropping the schema: <a href="classWt_1_1Dbo_1_1Session.html#4c1fedb21e4e1cc44b182a34e8ebb4efdropTables()">dropTables()</a>. <br />
    Added support for arbitrary queries in <a href="classWt_1_1Dbo_1_1Session.html#d39e953ef521eaa58c4c7e6ca1a6c19e">Session::query()</a>, including
    queries that do not return result or do not select from tables.</dd>
  <dt><a href="group__dbo.html#g8a2b653ff57f1459dfa2e556badd71d6">Dbo::field()</a></dt>
  <dd>Allow size suggestion for std::string and WString mappings</dd>
  <dt><a href="classWt_1_1Dbo_1_1SqlConnection.html">Dbo::SqlConnection, Dbo::SqlStatement</a></dt>
  <dd>Added support for floating point types, binary data (using std::vector&lt;unsigned char&gt;) and date and date/time types.<br/>
    Added methods for return dialect-specific information.<br/>
    Added properties API.<br/>
  </dd>
  <dt><a href="structWt_1_1Dbo_1_1sql__value__traits.html">Dbo::sql_value_traits</a></dt>
  <dd>Added support for backend-specific type mapping.</dd>
  <dt>(internal) DomElement</dt>
  <dd>Performance improvements in serializing the widgets to HTML
    and/or JavaScript</dd>
  <dt>Built-in httpd</dt>
  <dd>Added a configuration option <tt>--max-request-size</tt> to
  limit the size of a POST instead of the built-in default of 40
  MB<br/> Added a configuration option
  <tt>--max-memory-request-size</tt> to limit the size of a POST that
  is handed in-memory. Bigger POSTs are handled using a spool file.
  </dd>
</dl>

<hr />

<h2>Release 3.1.1 (February 17, 2010)</h2>

<p>The minimum boost version is now 1.36.</p>

<p>This release handles mostly bug fixes, with as most visible change
an update of the <i>polished</i> theme, which is now considered
complete.</p>

<h3>A) Security fixes:</h3>

Because of the following fixes for security problems, we recommend anyone
to upgrade live deployments of his application to the latest version.

<dl>
  <dt>Possible XSS vulnerability</dt>
  <dd>Fixed a possible XSS attack where a user follows a link to a Wt web
    application, taking advantage of unchecked insertions of the URL when
    redirecting to the canonical page.</dd>
  <dt>Possible UTF-8 vulnerability</dt>
  <dd>Form values and JSignal arguments received from the browser are
    now checked for sane UTF-8 encoding.</dd>
</dl>

<h3>B) New classes:</h3>

<dl>
  <dt><a href="classWt_1_1Dbo_1_1Dbo.html">Dbo/Dbo</a></dt>
  <dd>An optional base class for a database object, providing access to its
    id() and session().</dd>
</dl>

<h3>C) Main new features in existing classes:</h3>

<dl>
  <dt><a href="classWt_1_1WCanvasPaintDevice.html">WCanvasPaintDevice</a></dt>
  <dd>Now implements native text rendering on Firefox and latest
    Chrome and Safari browsers</dd>
  <dt><a href="classWt_1_1WInPlaceEdit.html">WInPlaceEdit</a></dt>
  <dd>Added a setEmptyText() method which sets the text to be
    displayed when value is empty.</dd>
  <dt><a href="classWt_1_1WPopupMenu.html">WPopopMenu</a></dt>
  <dd>Added an exec(WWidget *location, Orientation orientation) method which
    popups the menu besides another widget.</dd>
  <dt><a href="classWt_1_1WSuggestionPopup.html">WSuggestionPopup</a></dt>
  <dd>This class is now also style by the CSS theme.</dd>
  <dt><a href="classWt_1_1WTemplate.html">WTemplate</a></dt>
  <dd>Avoids now rerendering of already bound widgets when the
    template is rerendered.</dd>
  <dt><a href="classWt_1_1WTree.html">WTree</a>,
    <a href="classWt_1_1WTreeNode.html">WTreeNode</a>,
    <a href="classWt_1_1WTreeTable.html">WTreeTable</a>,
    <a href="classWt_1_1WTreeTableNode.html">WTreeTableNode</a>
  </dt>
  <dd>These widgets are now theme-aware, and tree decoration styling
    is provided by the theme. The setImagePack() APIs are now
    no-ops</dd>
  <dt><a href="classWt_1_1WWidget.html">WWidget</a></dt>
  <dd>Added positionAt() method which positions a widget (absolutely) besides
    another widget.</dd>  
  <dt><a href="classWt_1_1Chart_1_1WAxis.html">Chart/WAxis></a></dt>
  <dd>Added a setLabelFont() method.</dd>
  <dt><a href="classWt_1_1Http_1_1Request.html">Http/Request</a></dt>
  <dd>Added serverName(), serverPort(), path(), pathInfo(),
    queryString(), urlScheme(), in(), contentType(), contentLength(),
    userAgent() and clientAddress() methods which expose information
    form the HTTP request to WResources.</dd>
</dl>

<h3>D) Build changes:</h3>

<dl>
  <dt>XML_FEATURES</dt>
  <dd>This CMake option has been removed, and Mini-XML has been
    replaced by a modified RapidXML xml parser (mostly because of the
    hard-to-interpret Mini-XML license), but there are also nice
    performance improvements.</dd>
</dl>

<hr />

<h2>Release 3.1.0 (December 29, 2009)</h2>

<p>This release contains several new features and classes, after a long
  period of stabilization that happened before the 3.0.0 release.</p>

<h3>A) New classes:</h3>

<dl>
  <dt><a href="classWt_1_1WAggregateProxyModel.html">WAggregateProxyModel</a></dt>
  <dd>A model that provides support for drilling down through columns, supported
  by WTreeView.</dd>
  <dt><a href="classWt_1_1WCombinedLocalizedStrings.html">WCombinedLocalizedStrings</a></dt>
  <dd>Combines different localized strings implementations.</dd>
  <dt><a href="classWt_1_1WDateTime.html">WDateTime</a></dt>
  <dd>Combines a calendar date (WDate) and a clock time (WTime).</dd>
  <dt><a href="classWt_1_1WTemplate.html">WTemplate</a></dt>
  <dd>Use an XHTML fragment as a template, with variables that are place
  holders for strings or other widgets. See the blog example of how this
  class can be used to simplify HTML/CSS based layout of widgets and
  contents.</dd>
  <dt><a href="classWt_1_1WTime.html">WTime</a></dt>
  <dd>Represents a clock time (0-24 hours).</dd>
  <dt><a href="group__dbo.html">Wt::Dbo</a></dt>
  <dd>An Object Relational Mapping library. See the <a href="../../tutorial/dbo.html">tutorial here</a>.</dd>
</dl>

<h3>B) Main new features in existing classes:</h3>

Most inline CSS styles have been pushed out to an external style
sheet, which may be themed. The "default" theme provides the old look,
while a new "polished" theme provides a less boring (?) look for
several widgets (work in progress). The theme can be set using <a
href="classWt_1_1WApplication.html">WApplication::setCssTheme()</a>.

As a result, you will need to deploy Wt's <tt>"resources/"</tt>
folder, which contains the themes in <tt>"resources/themes/"</tt>, for
all but the most trivial applications.

<dl>
  <dt><a href="classWt_1_1Signal.html">Signal</a></dt>
  <dd>Added a template connect() method which may be given any function
  object, providing also support for the (future) c++1x lambda functions.</dd>
  <dt><a href="classWt_1_1WCanvasDevice.html">WCanvasDevice</a></dt>
  <dd>Several optimizations to output more concise JavaScript.</dd>
  <dt><a href="classWt_1_1WPaintedWidget.html">WPaintedWidget</a></dt>
  <dd>When width and/or height is not set using resize(), the widget
  will now properly react to layout management when put into a layout
  manager, triggering a server-side rerendering when needed.</dd>
  <dt><a href="classWt_1_1WSlider.html">WSlider</a></dt>
  <dd>A sliderMoved() signal was added which is fired whenever the slider is
  moved (but not yet released).</dd>
  <dt><a href="classWt_1_1WWidget.html">WWidget</a></dt>
  <dd>Added a find() method which searches the widget hierachy for a widget
  with a particular objectName().</dd>
  <dt><a href="classWt_1_1WServer.html">WServer</a></dt>
  <dd>Added an addResource() method to bind static resources to particular
  URLs (i.e. resources that are not bound to a specific session).</dd>
  <dt><a href="classWt_1_1Ext_1_1Container.html">Ext::Container</a></dt>
  <dd>Will now properly react to layout management from a layout that
  is set for a WContainerWidget.</dd>
  <dt><a href="classWt_1_1Ext_1_1FormField.html">Ext::FormField</a></dt>
  <dd>Added changed(), blurred() and focussed() signals.</dd>
  <dt><a href="classWt_1_1Chart_1_1WAxis.html">Chart::WAxis</a></dt>
  <dd>Added setAutoLimits() and autoLimits() methods to configure which limits
  are to be determined based on the data, and which are explicitly set.</dd>
  <dt><a href="classWt_1_1Chart_1_1WDataSeries.html">Chart::WDataSeries</a></dt>
  <dd>Added the setHidden() and hidden() methods to enable or disable
  a data series. Added setBarWidth() and barWidth() methods to set the
  width of a bar (useful mostly for scatter plots). Added
  setMarkerSize() and markerSize() methos.</dd>
  <dt><a
  href="classWt_1_1Chart_1_1WCartesianChart.html">Chart::WCartesianChart</a></dt>
  <dd>Use MarkerPenColorRole and MarkerBrushColorRole to override
  colors for makers on a per data point basis. Added mapFromDevice()
  and mapToDevice() methods for mapping device coordinates to chart
  coordinates and vice-versa</dd>
  </dl>

<h3>C) API Changes:</h3>

<dl>
  <dt><a href="classWt_1_1WSlider.html">WSlider</a></dt>
  <dd>Not really an API change, but the vertical slider is now showing
  the maximum value at its top side, not its bottom side.</dd>
  <dt><a href="classWt_1_1Chart_1_1WAxis.html">Chart::WAxis</a></dt>
  <dd>The minimum() and maximum() methods will now return the calculated
  minimum and maximum value when they are to be automatically calculated based
  on the data, configured using setAutoLimits()</dd>
</dl>

<h3>D) Build changes:</h3>

<dl>
  <dt>XML_FEATURES</dt>
  <dd>A new configuration option, XML_FEATURES, was added which allows the library to be built without MiniXML (and disabling fatures that require Mini-XML support). This configuration option is likely to be removed again in future versions.</dd>
  <dt>Documentation</dt>
  <dd>A <tt>doc</tt> directive was added, which uses doxygen and asciidoc tools
  to generate the reference documentation and tutorial.</dd>
  <dt>Tests</dt>
  <dd>Automated tests were added for non-interactive functionality,
  and are built by default.</dd>
</dl>

<hr />

<h2>Release 3.0.0 (November 3, 2009)</h2>

<p>
This release contains mostly bug fixes, build improvements and
documentation improvements compared to the latest pre-release
(2.99.5).
</p>

<p>
Most build improvements are related to finding the boost
libraries. Previously, Wt used a custom script, since CMake versions
&lt; 2.6 did not provide a good enough script for finding
boost. Starting with this release, when using CMake 2.6 or later, Wt
will use the script that comes with CMake. You can still fall back to
the script that comes with Wt, which is still used for older versions
of CMake, by defining one of the BOOST_COMPILER or BOOST_VERSION
variables.
</p>

<h3>A) New classes:</h3>

<i>No new classes</i>

<h3>B) Main new features in existing classes:</h3>

<dl>
  <dt><a href="classWt_1_1WDialog.html">WDialog</a></dt>
  <dd>It is now possible to have multiple modal dialogs, and nested
  recursive event loops.</dd>
  <dt><a href="classWt_1_1WWidget.html#e29fe35b633ec166f922419cd3ca9d96">
      WWidget</a></dt>
  <dd>The <samp>setDisabled()</samp> method moved up
  from <samp>WFormWidget</samp> to <samp>WWidget</samp>.</dd>
  <dt><a href="classWt_1_1JSlot.html#3d65b00a8015e556580527b52750ef87">
      JSlot</a></dt>
  <dd>The <samp>exec()</samp> method now passes object and event to the
    JavaScript event handler.</dd>
</dl>

<h3>C) API Changes:</h3>

<dl>
  <dt><a href="classWt_1_1WResource.html">WResource</a></dt>
  <dd>The handling of changes to the resource has been sanitized. A
  new method, <samp>setChanged()</samp> was added which must be called
  to notify users of the resource that the resource was changed. In
  addition to the existing <samp>generateUrl()</samp> which generates
  a new URL, a method was added which merely returns the existing
  URL: <samp>url()</samp>. With these improvements, a resource can
  effictively be shared by many view widgets and updated with the
  minimum of bandwidth usage.</dd>
</dl>

<hr />

<h2>Release 2.99.5 (September 1, 2009)</h2>

<p>
This release contains mostly bug fixes. The previous release (2.99.4)
contains some critical bugs that cause mayhem on IE, and a regression
with server push.
</p>

<hr />

<h2>Release 2.99.4 (August 27, 2009)</h2>

<p style="text-align: center">
  <b>!! This release contains bugs that render it unusable on IE !!</b>
</p>

<p>
This release contains mostly bug fixes and back-end improvements. The
most exciting new feature is the addition of a new bootstrap method,
which implements progressive enhancements (starting with a plain HTML
page, and then upgrading it to an AJAX page if the browser has
support), see
also <a href="/wt/doc/reference/html/overview.html#progressive_bootstrap">the
documentation</a>.
</p>

<h3>A) New classes:</h3>

<dl>
  <dt><a href="classWt_1_1WTableView.html">WTableView</a></dt>
  <dd>This is a simple MVC View class that renders tabular data
    in the most straight forward way using an HTML table element
  </dd>
</dl>

<h3>B) Main new features in existing classes:</h3>

<dl>
  <dt><a href="classWt_1_1Ext_1_1ToolBar.html#931b9b3e5d4cbbdee5394a841752c849">Ext::ToolBar</a></dt>
  <dd>Added insert() methods.</dd>
  <dt><a href="classWt_1_1WApplication.html#78016406c4746c56b2c2ffce7c5e181f">WApplication</a></dt>
  <dd>Added an enableAjax() method which notifies the application that
    a session is being enhanced with AJAX capabilities when using the
    progressive bootstrap method.</dd>
  <dt><a href="classWt_1_1WWidget.html#919a4eaf68ff52f06f6a726d55dfb768">WWidget</a></dt>
  <dd>Added an enableAjax() method which enhanced the widget with AJAX
    capabilities when using the progressive bootstrap method.</dd>
  <dt><a href="classWt_1_WCssDecorationStyle.html">WCssDecorationStyle</a></dt>
  <dd>Add support for custom cursors.</dd>
  <dt><a href="classWt_1_WWServer.html">WServer</a></dt>
  <dd>For FastCGI deployments, the proxy process which directs FastCGI
  requests to the correct session process is now also
  multi-threaded.</dd>
</dl>

<h3>C) API Changes:</h3>

<dl>
  <dt>The <a href="classWt_1_1WApplication.html#4a6f167bea94aefa8ba24f914c2fbee5">WApplication::notify()</a> behavior changed.</dt>
  <dd>Previously during a request, this method was called multiple
  times during event propagation and rendering of the
  application. Now, the method is called exactly once for each
  request. In this way, it becomes a useful entry point to also manage
  resource usage during (and inbetween) requests.</dd>
</dl>

<hr />

<h2>Release 2.99.3 (July 24, 2009)</h2>

<p>
This release contains mostly bug fixes and small feature
improvements. The most notable change that might affect existing
applications is a simplified internal path API behavior.
</p>

<h3>A) New classes:</h3>

<dl>
  <dt><a href="classWt_1_1WAbstractItemDelegate.html">WAbstractItemDelegate</a>
    and <a href="classWt_1_1WItemDelegate.html">WItemDelegate</a></dt>
  <dd><samp>WAbstractItemDelegate</samp> is a helper class used
    by <samp>WTreeView</samp> (and in the future perhaps other view
    classes) to render contents. The standard
    implementation, <samp>WItemDelegate</samp> maintains the default
    implementation that was previously integrated
    in <samp>WTreeView</samp>. The delegate will be responsible for
    editing features in <samp>WTreeView</samp> in the future, and in
    fact, you can already implement a custom item delegate that does
    editing if you cannot wait for it!
  </dd>
  <dt><a href="classWt_1_1Test_1_1WTestEnvironment.html">Test/WTestEnvironment</a></dt>
  <dd><samp>WTestEnvironment</samp> is an environment class which is useful for
    (unit) test-cases: it allows the instantiation of a
    <samp>WApplication</samp> so that you may include widgets in unit tests.
  </dd>
</dl>

<h3>B) Main new features in existing classes:</h3>

<h3>C) API Changes:</h3>

<dl>
  <dt>change of WApplication::internalPathChanged() semantics.</dt>
  <dd>The old behavior was that a single internal path change caused
  by the user (e.g. by moving forward/backword through his browser
  history) would cause repetitive invocations of internalPathChanged()
  with different arguments. The underlying idea was that this would
  make it easier to have the handling of internal path changes
  distributed over different objects. It caused however more problems
  than it solved. The new behavior is now that it is invoked exactly
  one time, and the argument is simply the new internal path.</dd>
</dl>

<hr />

<h2>Release 2.99.2 (May 29, 2009)</h2>

<p>
This release contains mostly build improvements, bug fixes, and API cleanups.
</p>

<h3>A) New classes:</h3>

<dl>
  <dt><a href="classWt_1_1Http_1_1Client.html">Http/Client</a></dt>
  <dd><samp>Client</samp> is a utility class to bootstrap a new Wt
  application.</dd>
</dl>

<h3>B) Main new features in existing classes:</h3>

<dl>
  <dt><a href="classWt_1_1Ext_1_1FormField.html">Ext::FormField</a></dt>
  <dd>Add setFocus() method.</dd>
  <dt><a href="classWt_1_1Ext_1_1ToolBar.html">Ext::ToolBar</a></dt>
  <dd>Added an addStretch() method (contributed by David Galicia).</dd>
  <dt><a href="classWt_1_1Http_1_1Response.html">Http::Response</a></dt>
  <dd>Added a continuation() method.</dd>
  <dt><a href="classWt_1_1WCheckBox.html">WCheckBox</a></dt>
  <dd>Add support for tri-state checkboxes. These are also supported
  by item models and WTreeView.</dd>
  <dt><a href="classWt_1_1WWDialog.html">WDialog</a></dt>
  <dd>Support for non-modal dialogs and interactive moving.</dd>
  <dt><a href="classWt_1_1WFormWidget.html">WFormWidget</a></dt>
  <dd>New methods setReadOnly() and isReadOnly().</dd>
  <dt><a href="classWt_1_1WGridLayout.html">WGridLayout</a></dt>
  <dd>Support a row stretch value of -1, which is like 0 but will still
  manage the height of cells (allowing their contents to fill the entire
  cell).</dd>
  <dt><a href="classWt_1_1WPaintDevice.html">WPaintDevice</a></dt>
  <dd>Support update rendering (not erasing the current canvas) using
  paint flags.</dd>
</dl>

<h3>C) API Changes:</h3>

<dl>
  <dt>WFileUpload::isUploaded() was deprecated</dt>
  <dd>The name was not covering its actual behavior: instead of
  checking whether a file has been uploaded, it returns whether true
  when a call to upload() is not needed. You should replace any call
  to isUploaded() with the new method
  <a href="classWt_1_1WFileUpload.htm#66376fb4668a037760a91abad9f83f8al">!canUpload()</a> (<b>note the inversion!</b>.</dd>
</dl>

<hr />

<h2>Release 2.99.1 (Mar 20, 2009)</h2>

<p>
This release contains only build improvements, bug fixes, and API cleanups.
</p>

<hr />

<h2>Release 2.99.0 (Mar 4, 2009)</h2>

<p>
This release is a preview for Wt 3.0.0. Many things have changed both
in the internals and the API. This is the first release that provides
several API changes which are not backward compatible (some of which
were post-poned until now).

Please read the following notes carefully, especially sections C) and
D), to understand what changes to expect and how to adapt existing
applications.
</p>

<p>
Support for the C++ boost library &lt; 1.35 has been dropped: Wt now
requires at least boost >= 1.35.0.
</p>

<h3>A) New classes:</h3>

<dl>
  <dt><a href="classWt_1_1WFlags.html">WFlags</a></dt>
  <dd><samp>WFlags</samp> is a utility class that provides a type-safe ORing of
  enum flags. It is used everywhere in the Wt API where previously an
  <samp>int</samp> was used to allow enums to be ORed together.</dd>
  <dt><a href="classWt_1_1WGoogleMap.html">WGoogleMap</a></dt>
  <dd>This is a widget, contributed by Richard Ulrich, that displays a
  Google map.</dd>
  <dt><a href="classWt_1_1Http_1_1Request.html">Http::Request</a>, <a href="classWt_1_1Http_1_1Response.html">Http::Response</a>, <a href="classWt_1_1Http_1_1ResponseContinuation.html">Http::ResponseContinuation</a> and <a href="classWt_1_1Http_1_1UploadedFile.html">Http::UploadedFile</a></dt>
  <dd>These are utility classes which model an HTTP request and
  response and that are used in the new <samp>WResource</samp> API.</dd>
</dl>

<h3>B) Main new features in existing classes:</h3>

<dl>
  <dt><a href="classWt_1_1WApplication.html#d9631ca64e68d30d40cb49c90e55223d">WApplication::enableUpdates()</a></dt>
  <dd>Server-initiated updates (aka "server push") has been
  reimplemented and now works reliably in all situations, including in
  the presence of intermediate proxies. The dependency on the 3rd
  party JS orbited library has been removed and replaced with a simple
  XHR-based solution.</dd>
  <dt><a href="classWt_1_1WButtonGroup.html">WButtonGroup</a></dt>
  <dd>Various methods were added: id's may be associated with a specific
  radio buttons, which may be used to identify a particular button.</dd>
  <dt><a href="classWt_1_1WDatePicker.html">WDatePicker</a></dt>
  <dd>Is now easier to use because of a sensible default constructor
  that also creates the line edit using a <samp>WDateValidator</samp>,
  and creates the icon which is associated with the popup.</dd>
  <dt><a href="classWt_1_1WFileResource.html">WFileResource</a></dt>
  <dd>Uses the continuation support in the new <samp>WResource</samp> API
  to transmit the file in chunks.</dd>
  <dt><a href="classWt_1_1WLength.html">WLength</a></dt>
  <dd>WLength::Auto was added, is a synonym for WLength()</dd>
  <dt><a href="classWt_1_1WSuggestionPopup.html">WSuggestionPopup</a></dt>
  <dd>Is now also an MVC View widget, reading its data from a
  <samp>WAbstractItemModel</samp></dd>
  <dt><a href="classWt_1_1WTable.html">WTable</a></dt> <dd>New method
  setHeaderCount() to specify the number of first rows or columns that
  should be rendered as an HTML table header
  (<samp>&lt;th&gt;</samp>).</dd>
  <dt><a href="classWt_1_1WWidget.html">WWidget</a></dt>
  <dd><p>New virtual method <samp>rerender()</samp> which allows a
  widget to prepare itself before rendering (and defer internal
  changes until that time). A widget may ask to be rerendered using
  <samp>askRerender()</samp></p> <p><samp>Widget</samp> no longer
  inherits from <samp>WResource</samp>, but instead inherits directly from
  <samp>WObject</samp>. It was simply a bad idea, and not useful for
  anything.</p></dd>
</dl>

<h3>C) Changes that break existing applications:</h3>

<dl>
  <dt>1) Signals are no longer public members</dt>
  <dd><p>Instead, they are now accessor member functions:
  e.g. <samp>WInteractWidget::clicked</samp> has been renamed to
  <samp>WInteractWidget::clicked()</samp>. This has as major benefit
  that signals can be created on-demand, which leads to drastically
  lower memory usage and signifcant speedups especially on embedded
  systems.</p> <p>The change requires that everywhere in your code
  where you access a signal, you will need to change to add
  parentheses. For consistency, you may also want to
  use the same convention for your own widget classes that define
  signals.</p></dd>
  <dt>2) <a href="classWt_1_1WResource.html">WResource</a></dt>
  <dd><p>The API has been redesigned and greatly simplified. If you are
  implementing your own resources, then you will need to redesign your
  implementation. The new API is simpler (requires only one virtual
  method to be implemented) and more powerful, providing support for
  <i>continuations</i> to serve large resources without blocking a
  thread or requiring large memory usage.</p>
  <p>In addition, resources have better thread-safety: they are now by
  default reentrant (requests for a single resource may be handled
  concurrently) and they are protected from concurrently being
  destroyed by the main event loop.</p></dd>
  <dt>3) <a href="classWt_1_1WValidator.html">WValidator</a></dt>
  <dd><p>The signature for the virtual <samp>validate()</samp> method was
  changed: parameter <samp>pos</samp> which was ignored anyway has
  been removed.</p></dd>
  <dt>4) <a href="classWt_1_1WEnvironment.html">WEnvironment</a></dt>
  <dd><p>The methods <samp>getArgument()</samp> and
  <samp>arguments()</samp> were renamed to respectively
  <samp>getParameter()</samp> and <samp>getParameterMap()</samp>. The
  signature for <samp>getParameter()</samp> is also different as it
  returns a pointer to a string, which is 0 when the parameter is not
  defined, instead of the olde behaviour of throwing an
  exception. There is a new method that allows to read all values for
  a parameter, <samp>getParameterValues()</samp></p></dd>
  <dt>5) <a href="classWt_1_1ModelIndex.html">WModelIndex</a></dt>
  <dd><p>The 20-byte SHA1 hash based internal pointer has been removed
  again as the object increase and overhead could not be justified.</p></dd>
</dl>

<h3>D) Deprecated API that was removed:</h3>

These are API calls that were deprecated in earlier releases, and have now
been completely removed from the library:

<dl>
  <dt><samp>WApplication::applicationName()</samp></dt>
  <dd>Use <a
  href="classWt_1_1WApplication.html#ab6320ecdd0e8e4026e9ef1aca710ca5">
  WApplication::internalPath()</a> instead.</dd>
  <dt><samp>WApplication::setState()</samp></dt>
  <dd>Use <a
  href="classWt_1_1WApplication.html#2c1a10aadc0d7ed877b5715b42ca4911">WApplication::setInternalPath()</a>
  instead.</dd>
  <dt><samp>WApplication::state()</samp></dt>
  <dd>Use <a
  href="classWt_1_1WApplication.html#ab6320ecdd0e8e4026e9ef1aca710ca5">
  WApplication::internalPath()</a> instead.</dd>
  <dt><samp>WApplication::stateChanged</samp></dt>
  <dd>Use <a
  href="classWt_1_1WApplication.html#3e68c4b6bb387f27a614e7962e11967b">WApplication::internalPathChanged()</a>
  instead.</dd>
  <dt><samp>WRegExpValidator::WRegExpValidator(const boost::regex&amp;)
  </samp></dt>
  <dd>Use the <a
  href="classWt_1_1WRegExpValidator.html#7536b67e2bedd2dfdb5b89c9dd56602b">WRegExpValidator(const
  WString&amp;)</a> constructor instead.</dd>
  <dt><samp>WPainterPath::drawArc(..., width, height, ...)</samp></dt>
  <dd>An elliptical arc segment could not be support on all devices.</dd>
  <dt><samp>WTable::numRows()</samp></dt>
  <dd>Use <a href="classWt_1_1WTable.html#79d5dfe40ee5e67c5007ee370e8cd2f3">WTable::rowCount()</a>.</dd>
  <dt><samp>WTable::numColumns()</samp></dt>
  <dd>Use <a
  href="classWt_1_1WTable.html#4d062330d1c9b3f202985b92dcb59d4f">WTable::columnCount()</a>
  instead.</dd>
  <dt><samp>WText::setFormatting()</samp> and
  <samp>WText::formatting()</samp></dt>
  <dd>Use <a href="classWt_1_1WText.html#f22c64c4c5fed3d2aef0915a7e5c5866">WText::setTextFormat()</a> and
  <a href="classWt_1_1WText.html#c0976c36c5181a534f161ca3724d4296">WText::textFormat()</a> instead.</dd>
</dl>

<hr />

<h2>Release 2.2.3 (Jan 26, 2009)</h2>

<p>This release is a maintenance release, with mostly bug fixes and
feature improvements.</p>

<h3>A) Main new features in existing classes:</h3>

<dl>
  <dt><a href="classWt_1_1WAbstractItemModel.html">WAbstractItemModel</a>:</dt>
  <dd><samp>const char *</samp> data in <samp>boost::any</samp> is now
    also supported.</dd>
  <dt><a href="classWt_1_1WAbstractProxyModel.html">WAbstractProxyModel</a>:
  </dt><dd>Implemented <samp>toRawIndex()</samp>
    and <samp>fromRawIndex()</samp> so that indexes can be recovered
    when the model's layout is changed, if the underlying model
    provides implementations for <samp>toRawIndex()</samp>
    and <samp>fromRawIndex()</samp>.</dd>
  <dt><a href="classWt_1_1WComboBox.html">WComboBox</a>:</dt>
  <dd>Also supports <samp>StyleClassRole</samp> data role for items</dd>
  <dt><a href="classWt_1_1WDialog.html">WDialog</a>:</dt>
  <dd>New method <samp>setTitleBarEnabled()</samp> to disable the default
  title bar.</dd>
  <dt><a href="classWt_1_1WMenu.html">WMenu</a>:</dt>
  <dd>New method <samp>removeItem()</samp>, only works when rendered as a
    list.</dd>
  <dt><a href="classWt_1_1WTabWidget.html">WTabWidget</a>:</dt>
  <dd>New method <samp>removeTab()</samp>.</dd>
  <dt><a href="classWt_1_1WTreeView.html">WTreeView</a>:</dt>
  <dd><ul>
      <li>New method <samp>setColumn1Fixed()</samp> to fix the first
    column while scrolling horizontally through the other columns.</li>
      <li>New method <samp>setColumnFormat()</samp> to control formatting of
    data.</li>
      <li>New method <samp>setColumnBorder()</samp> to set the
    internal column border color.</li>
      <li>New method <samp>setColumnResizeEnabled()</samp> to disable resize
    handles.</li>
      <li>The view now also reacts correctly to insertion and
    removal of model columns.</li>
    </ul>
  </dd>
</dl>

<h3>B) New examples</h3>

<dl>
  <dt><a href="http://www.webtoolkit.eu/wt/examples/gitmodel/gitview.wt">
      gitmodel:</a></dt>
  <dd>An example that demonstrates how to implement a custom abstract
    item model.</dd>
  <dt><a href="http://www.webtoolkit.eu/wt/examples/treeview-dragdrop/treeview-dragdrop.wt">treeview-dragdrop</a>:</dt>
  <dd>An example that demonstrates drag and drop support in WTreeView.</dd>
</dl>

<h3>C) Changes that break backward compatibility</h3>

<dl>
  <dt><a href="classWt_1_1WApplication.html">WApplication</a>:</dt>
  <dd><samp>useStyleSheet()</samp> only supports a subset of IE condition
    strings, since the string is now parsed by Wt rather than by IE (when
    dynamically loading stylesheets, the comment-syntax does not work
    reliably).</dd>
</dl>

<hr />

<h2>Release 2.2.2 (Dec 1, 2008)</h2>

<p><i>As of now, we will also be listing noteworthy new API features,
even if they are no concern for backwards compatibility.</i></p>

<h3>A) New classes:</h3>

<dl>
  <dt><a href="classWt_1_1WPopupMenu.html">WPopupMenu</a>,
    <a href="classWt_1_1WPopupMenuItem.html">WPopupMenuItem</a>:</dt>
  <dd>A popup menu, which you would typically use to present a
  context menu.</dd>
  <dt><a href="classWt_1_1WAbstractProxyModel.html">WAbstractProxyModel</a>,
    <a href="classWt_1_1WSortFilterProxyModel.html">WSortFilterProxyModel</a>:</dt>
  <dd>Proxy models, which present data from a source model in a
  different way.</dd>
  <dt><a href="classWt_1_1WLoadingIndicator.html">WLoadingIndicator</a>, <a href="classWt_1_1WDefaultLoadingIndicator.html">WDefaultLoadingIndicator</a>,
  <a href="classWt_1_1WOverlayLoadingIndicator.html">WOverlayLoadingIndicator</a>:</dt>
  <dd>Customizable loading indicators.</dd>
</dl>

<h3>B) Main new features in existing classes:</h3>

<dl>
  <dt><a href="classWt_1_1WTreeView.html">WTreeView</a>, <a href="classWt_1_1WAbstractItemModel.html">WAbstractItemModel</a>:</dt>
  <dd>The WAbstractItemModel interface was extended to allow handling
  of drag &amp; drop events, and WTreeView now is able to start
  dragging and handle dropping of item selections and other data.</dd>
  <dt><a href="classWt_1_1JSignal.html">JSignal</a>:</dt>
  <dd>You can now pass the original (keyboard/mouse) JavaScript event
  as a parameter to custom signals.</dd>
  <dt><a href="classWt_1_1WTreeView.html">WTreeView</a>:</dt>
  <dd>access mouse event in itemClicked, doubleClicked and
  mouseWentDown signals.</dd>
  <dt><a href="classWt_1_1WServer.html">WServer</a>:</dt>
  <dd>Support for widget-set mode, allowing a Wt application to be
  embedded in an existing web page/application.</dd>
</dl>

<h3>C) Changes that break backward compatibility</h3>

<p>This release does not contain changes that break existing
applications.</p>

<hr />

<h2>Release 2.2.1 (Nov 3, 2008)</h2>

<p>This release is as usually a mix of bug fixes, improvements and new
features.</p>

<p>We have made a significant change to the MVC system, which will
break existing program code in case you have implemented your own
models (i.e. deriving from <samp>WAbstractItemModel</samp>) or views
widgets (i.e. components that listen to model changes).</p>

<p>
The <samp>WAbstractItemModel</samp> interface was changed to support
hierarchical models. This means that most methods will now take an
extra parameter that specifies the parent <samp>WModelIndex</samp>,
and also all signals have now this extra parameter. Because the
parameter has a default value of WModelIndex() which corresponds to
the top level parent, the API is largely backwards compatible when
merely using the model. It is only those classes that reimplement the
interface, or listen to signal events, that are affected.
</p>

<p>
The immediate benefit of the new <samp>WAbstracItemModel</samp>
interface is that it allows us to implement View widgets like the new
<samp>WTreeView</samp> widget.
</p>

<hr />

<h2>Release 2.2.0 (Sept 12, 2008)</h2>

<p>This release has a rather substantial rewrite (and simplification)
of Wt's bootstrapping process. In the past, Wt used a frameset trick
to be able to load the AJAX-based skeleton when JavaScript was
available. Isntead, now, the entire AJAX-based stuff is loaded
directly into the bootstrap page. A benefit of the new approach is
that we avoid iframe tricks, which have been deprecated from strict
HTML and XHTML. But, it was in fact motivated in the first place to
support all major browsers for a new internal path API. This new API
allows to fully support URL changes and bookmarks in a unified way
(i.e. it works equally when the browser supports AJAX, no JavaScript,
or is a bot such as google bot).</p>

<p>As a consequence, this release contains the following changes that
may break your application:</p>

<ul>
  <li><samp>WMenu::enableBrowserHistory()</samp> and <samp>WMenu::browserHistoryId()</samp> have been removed, use the new methods <samp>WMenu::setInternalPathEnabled()</samp> and <samp>WMenu::setInternalBasePath()</samp>
  </li>
  <li><samp>WMenuItem</samp> has been reorganized, and if you have
  specialized WMenuItem you will need to adapt your reimplementation
  to the new virtual interface. In the new interface, you need to
  reimplement <samp>WMenuItem::createItemWidget()</samp> and
  <samp>WMenuItem::updateItemWidget()</samp> allowing you to react to
  item changes (internal path or text). The default implementation now
  always uses a WAnchor.</li>
  <li><samp>WApplication::setState()</samp>, <samp>WApplication::state()</samp> and <samp>WApplication::stateChanged</samp> have been deprecated. It is stronly advised that you use the new internal path API instead. This does require you to treat different parts of the state as a file hierarchy. See the <samp>WApplication::setInternalPath() documentation</samp>.
  </li>
</ul>

<p>
  The following methods have been deprecated (but are still supported):
</p>
<ul>
  <li><samp>WTable::numRows()</samp> has been renamed
  to <samp>WTable::rowCount()</samp>.</li>
  <li><samp>WTable::numColumns()</samp> has been renamed
  to <samp>WTable::columnCount()</samp>.</li>
</ul>

<hr />

<h2>Release 2.1.5 (July 25, 2008)</h2>

<p>Wt now installs its include files in a Wt/ subdirectory. You may
want to change your build files to pick up this new include directory,
or, change your code to scope the include files to look like
#include&lt;Wt/WLineEdit&gt; instead of #include&lt;WLineEdit&gt;</p>

<p>This release contains the following changes that may break your
application:</p>

<ul>
  <li><samp>WText</samp> will validate XHTML text when it is set to the
   widget. The old behaviour was to validate only before
   rendering. The change was needed to be able to react to XML parse
   errors. As a consequence if you are creating a WText with text that
   is not valid XML, followed by a
   call <samp>setFormatting(WText::PlainFormatting)</samp>, you should
   change this now to use the new <samp>WText</samp> constructor which
   takes the TextFormat as a new argument: <samp>new WText(text,
   Wt::PlainText, parentWidget)</samp>
  </li>
  <li><samp>WContainerWidget::setLayout(WLayout *layout, bool fitWidth, bool
   fitHeight)</samp> has been replaced with the more generic
   <samp>WContainerWidget::setLayout(WLayout *layout, int
   alignment)</samp>.
  </li>
</ul>

<p>
  The following methods and enumerations have been deprecated (but are
  still supported):
</p>
<ul>
  <li><samp>enum WText::Formatting</samp> has been renamed
  to <samp>Wt::TextFormat</samp>. The old values map as follows on new
  values:
    <ul>
      <li><samp>WText::XHTMLFormatting</samp> becomes <samp>Wt::XHTMLText</samp>;</li>
      <li><samp>WText::XHTMLUnsafeFormatting</samp> becomes <samp>Wt::XHTMLUnsafeText</samp></li>
      <li><samp>WText::PlainFormatting</samp> becomes <samp>Wt::PlainText</samp></li>
    </ul>
  </li>
  <li><samp>WText::setFormatting()</samp> has been renamed
  to <samp>WText::setTextFormat()</samp> and
  <samp>WText::formatting()</samp> has been renamed
  to <samp>WText::textFormat()</samp>.</li>
</ul>

<hr />

<h2>Release 2.1.4 (July 4, 2008)</h2>

<p>The following has changed for building Wt:</p>

<ul>
  <li>The CMake variable CONFIGURATION (which defaulted to
  /etc/wt/wt_config.xml) is no longer used, but instead there is now a
  CONFIGDIR (/etc/wt/) which is used to store configuration
  files.
  </li>
</ul>

<p>The following has changed in the wt_config.xml file:</p>

<ul>
  <li>The &lt;valgrind-path&gt; setting for the FCGI connector may now
    be a command-line including arguments</li>
</ul>

<p>This release should not contain changes that may break your
application.</p>

<hr />

<h2>Release 2.1.3 (May 20, 2008)</h2>

<p>This release should not contain changes that may break your
application.</p>

<hr />

<h2>Release 2.1.2 (April 14, 2008)</h2>

<p>The following changes may break your application build:</p>

<ul>
  <li><samp>WTreeNode::expanded()</samp> has been renamed
  to <samp>WTreeNode::isExpanded()</samp>.</li>
</ul>

<hr />

<h2>Release 2.1.1 (April 10, 2008)</h2>

<p>This release should not break any of your applications, but we did
 deprecate some methods and enumeration types. You are advised to
 migrate to the replacements methods since we will discontinue support
 for the older ones in the future.</p>

<p>
  The following methods and enumerations have been deprecated:
</p>
<ul>
  <li><samp>enum SelectionUnit</samp> has been renamed
  to <samp>SelectionBehavior</samp>. The old values map as follows on new
  values: <samp>CellSelection</samp> becomes <samp>SelectItems</samp>;
    <samp>RowSelection</samp> becomes <samp>SelectRows</samp>.</li>
  <li><samp>WWidget::setOffset(int sides, WLength)</samp> is deprecated,
  and the new method is <samp>WWidget::setOffsets(WLength, int
  sides)</samp>: the argument order has been switched to be consistent
  with the method signature of <samp>setMargin()</samp>
  and <samp>setPadding()</samp>.</li>
  <li><samp>WResource::suggestFilename()</samp> has been renamed to
  <samp>WResource::suggestFileName()</samp>.</li>
</ul>

<p>
  The following changes affect run-time behaviour:
</p>
<ul>
  <li><samp>WTreeNode</samp> now supports a policy for when to show a child count
  indication. The old behaviour was to always show the child count.
  Now, by default this option is disabled. Use
  <samp>WTreeNode::setChildCountPolicy(Enabled)</samp> to get the old
  behaviour back, if you wish.</li>
</ul>

<hr />

<h2>Release 2.1.0</h2>

<p>The library dependencies have changed slightly.</p>

<p>
To build Wt 2.1.0, you need:
</p>
<ul>
  <li>CMake 2.4 or later</li>
  <li>boost 1.34.1 (boost 1.33.1 might should still work, but is
    not recommended)</li>
  <li>asio 0.3.9: either the boost or non-boost version <i>(only
      for the http connector)</i></li>
  <li><i>optionally</i>, openssl for HTTPS support <i>(only for the http
      connector)</i></li>
  <li><i>optionally</i>, libz for gzip compression support <i>(only for
      the http connector)</i></li>
  <li>fcgi library, including C++ bindings (libfcgi++)<i>(only for the
      fcgi connector)</i></li>
</ul>
<p>Furthermore, the Wt::Ext library has been upgraded and now wraps
around the extjs 2.x library, instead of extjs 1.x.</p>

<p>Some API changes may need a porting effort:
</p>
  <ul>
    <li><samp>Ext::ProgressDialog</samp>: doesn't show by default, you
    need to call show() to show the dialog.</li>
    <li><samp>Ext::ContentPanel</samp>, <samp>Ext::BorderLayout</samp> have
    been removed. They have been replaced with a stand-alone layout
    system, that may manage contents in
    an <samp>Ext::Container</samp>. The layout system provides
    <samp>WBorderLayout</samp> and several other layout managers.</li>
    <li><samp>WSignalMapper</samp> has been expanded to allow mapping of
      signals with an extra argument, which is passed to the mapped
      signal. Because of this, the signature of the class has been
      expanded with an extra template argument. If you have forward
      declarations to <samp>WSignalMapper</samp>, you will need to modify
      these too (or simply include <samp>WSignalMapper</samp>).</li>
    <li><samp>WAnchor</samp>: no longer uses a <samp>WLabel</samp> internally,
      and the label-releated methods have been removed.</li>
  </ul>

<hr />

<h2>Release 2.0.5</h2>

<ul>
  <li><samp>WDialog</samp> (and <samp>WMessageBox</samp>) usage changed, and
    is now more like Qt. When you are not
    using <samp>WDialog::exec()</samp> or <samp>WMessageBox::show(...)</samp>,
    then you must explictly <samp>show()</samp> the dialog to show it. You
    can now also <samp>hide()</samp> the dialog if you want.
  </li>
  <li>
    Moved several enums from within classes to the Wt namespace. This is
    likely to break your code at compile time when you are using one. The
    fix is to remove the class scope from the enum type or value.
    <ul>
      <li><samp>WScrollArea::Orientation</samp> -> <samp>Wt::Orientation</samp></li>
      <li><samp>WMenu::Orientation</samp> -> <samp>Wt::Orientation</samp></li>
      <li><samp>WMessageBox::StandardButton</samp> -> <samp>Wt::StandardButton</samp></li>
      <li><samp>WMessageBox::Icon</samp> -> <samp>Wt::Icon</samp></li>
    </ul>
  </li>
</ul>

<hr />

<h2>Release 2.0.4</h2>

<i>Important: 2.0.4a contains a fix for a bug introduced in 2.0.4 that
  reset the deploy-path in wthttpd.</i>

<p>
  This release adds a few new features:
</p>
  <ul>
    <li><samp>WComboBox</samp> (and <samp>WSelectionBox</samp>) now use
      a <samp>WAbstractItemModel</samp> in a more flexible model/view
      system.</li>
    <li>Stylesheets may be browser-conditional (by Patrick Fischer)</li>
    <li>wthttpd may serve custom error pages (by Patrick Fischer)</li>
    <li><samp>WResource</samp> can now access HTTP GET or POST query
      arguments. This will break your code (at compile time) if you
      have implemented your own <samp>WResource</samp>, since the signature of the
      <samp>streamResourceData()</samp> method has been changed to pass
      the arguments map as a second parameter.</li>
  </ul>

<hr />

<h2>Release 2.0.1</h2>

<p>
  This release fixes some build-related problems, as well as smaller
  bugs. The main improvement in this release is related to use of Wt
  in resource-constrained embedded systems.
</p>

<p>
  The most visible change is that the dependency on the Xerces C++ XML
  library was dropped in favour of the much smaller Mini-XML
  library. The draw-back is a reduction of supported character
  encodings to only UTF8 and UTF16, next to the default locale character
  encoding (which is typically an 8-bit flavour).
</p>

<p>
  When using the built-in httpd, you can now disable support for SSL
  at compile time, freeing a number of SSL-related dependencies.
</p>

<p>
  In the API, more comparison operators (== and !=) were added to
  WString, and a WViewWidget was added for simple MVC widgets (with
  the main purpose to reduce session-state at the server).
</p>

<hr />

<h2>Release 2.0.0</h2>

<p>
  This release contains numerous changes which are likely to cause some
  porting effort for Wt 1.1.x applications to work properly.
</p>

<p>
<b>If you are upgrading from a 1.99.x release, you will notice that
some of these notes have actually evolved, especially with respect to
WString and unicode support.</b>
</p>

<p>
  Here is a list of changes with respect to Wt 1.1.x that are likely
  to require your attention, and some tips on how to do the porting.
</p>

<h4>1) Namespace Wt</h4>

<p>All Wt classes are now inside the namespace <samp>Wt</samp>.</p>

<p>To handle this change, you will need to:
</p>
  <ul>
    <li>Wrap forward declarations to Wt widgets in header files inside a
      Wt namespace, or <samp>#include &lt;WFwdDeclarations&gt;</samp></li>
    <li>and scope all Wt classes with <samp>Wt::</samp>, </li>
    <li>or import the Wt namespace: <samp>using namespace Wt;</samp></li>
  </ul>

<h4>2) WString</h4>

<p>
  Previously, most widgets offered double methods that either used a
  <samp>std::string</samp> for literal text, or a
  <samp>WMessage</samp> for localized text.
</p>

<p>
  In the new release, widgets use <samp>Wt::WString</samp> for both
  literal and localized text. WString offers unicode support for both
  literal as well as localized text. To create a literal string,
  simply assign or construct a Wt::WString from that string. The
  strings supported or both narrow and wide C and C++ strings. UTF8
  encoded narrow strings may also be converted. To create a localized
  string, use one of the static methods <samp>WString::tr(const
  std::string key)</samp> and <samp>WWidget::tr(const std::string
  key)</samp>.
</p>

<p>
  To help with legacy code, WMessage is now a typedef for WString, but
  is deprecated and should not be used in new code. Unfortunately, the
  constructors <samp>WMessage(const char *text)</samp> and
  <samp>WMessage(const std::string text)</samp>, changed meaning!
  While previously they took a key to construct a localized message,
  they now take a literal text (the exact opposite!), since they are
  in fact plain WString() constructors. As a consequence your application
  will display key values instead of resolving those values (but will
  not break entirely).
</p>
<p>
  The new approach offers the benefit of only requiring one method
  signature for both literal and localizable text. This not only
  simplifies our work, but more importantly by using
  <samp>WString</samp> for displayed text in the API of your own
  widgets, localization (including the automatic language switching)
  comes automatically and is decided on by the user of your widget.
</p>
<p>
  Fortunately, there is a straightforward trick to handle most consequences
  of this change:
</p>
  <ul>
   <li>Replace <samp>WMessage(...)</samp> with <samp>tr(...)</samp>,</li>
   <li>add <samp>.value()</samp> when using the result of functions such
     as <samp>WText::text()</samp>,</li>
   <li>change your own classes to use <samp>WString</samp>
     wherever they expect some text that will be displayed, instead of
     std::string or WMessage.</li>
  </ul>

<h4>3) Wide string API</h4>

<p>
  Since Wt 2.0.0, the API for Wt has been changed to use WString
  instead of C++ narrow strings. WString supports both narrow and wide
  strings, and provides conversion between both. It does not provide
  string operations, however, and instead acts as a string
  container. You should convert to a C++ string type to perform
  operations. You should also not use WString outside of the user
  interface part of your application.
</p>

<h4>4) No more wmain()</h4>

<p>
  Previously, the Wt library implemented the <samp>main(int argc, char
  **argv)</samp> function, and called a <samp>wmain()</samp> function
  which created the WApplication instance.
</p>
<p>
  Wt 2.0.0 allows multiple applications to run within a single process.
  Therefore, the <samp>WApplication::exec()</samp> approach was no longer
  feasible. The new approach requires that:
</p>

  <ul>
    <li>your main function should look like this:
<pre>
int main(int argc, char **argv)
{
  return Wt::WRun(argc, argv, &amp;createApplication);
}
</pre>
    </li>
    <li>where createApplication is a function of the following
      signature:

<pre>
Wt::WApplication *createApplication(const Wt::WEnvironment&amp; env)
{
  // return a new application object.
}
</pre>

    </li>
  </ul>

<h4>5) Configuration in /etc/wt/wt_config.xml</h4>

<p>
  Wt 2.0.0 uses a configuration file for a number of settings that 
  could previously be configured at build time of the library, or
  in the API. The latter functions are:
</p>
<ul>
  <li><samp>WApplication::setMaximumRquestSize()</samp></li>
  <li><samp>WApplication::setIdleTimeout()</samp></li>  
</ul>

<h4>6) Removed obsolete classes</h4>

<p>
  Wt 2.0.0 removed a number of classes that were still in the widget
  tree, but have been obsoleted by more flexible classes:
</p>
<ul>
  <li><samp>WAbstractTab</samp>, <samp>WButtonTab</samp>, and <samp>WTabWidget</samp> are obsoleted by the more flexible <samp>WMenu</samp>.</li>
</ul>

<h4>7) Deprecate boost::regex from WRegExpValidator API</h4>

<p>
  The constructor and methods that takes a boost::regex object in
  the WRegExpValidator API have been deprecated, to remove the dependency
  on boost from the public API. You should consider the std::string based
  construtor and method instead.
</p>

<h4>8) WObject::emit() has been removed.</h4>

<p>
  Since Wt 1.99.1, we have removed WObject::emit() function. Instead,
  you may simply call the signal with its arguments, or use the
  explicit emit method (recommended).</p>

<p>
  To adapt your code, you should:
</p>
  <ul>
    <li>Replace all <samp>emit(MySignal(...))</samp> with <samp>MySignal(...)</samp> or <samp>MySignal.emit(...)</samp>
    </li>
  </ul>

<h4>9) WResource::streamResourceData() signature has changed.</h4>

<p>
  Since Wt 2.0.0, WResource::streamResourceData() returns a boolean value
  which indicates if all data has been streamed. If you have reimplemented
  WResource for your applications, you must update the signature and return
  true.
</p>
<p>
  The change is relevant only within the new server-push support that is
  now in Wt 2.0.0. This allows you to continuously append to the content
  of a resource.
</p>

<h4>10) Rename of WJavascriptSlot to JSlot.</h4>

<hr />

<h2>Release 1.1.7</h2>

This release contains lots of additions and improvements, but should
be completely backwards-compatible.

<hr />

<h2>Release 1.1.6</h2>

There is one change which will impact the behaviour of current applications:
Currently, on exit, by default the last widget updates are shown. So, no
more good-bye message. This changes slightly when one needs to redirect()
to a new location: not when WApplication::exec() returns, but during the
same event handling as when calling WApplication::quit().

<hr />

<h2>Release 1.1.5</h2>

Nothing special...

<hr />

<h2>Release 1.1.4</h2>

Changes to impact everybody, since the previous release:

<ul>
<li>
  The dependency for libxml++ (and its large number of dependencies) has
  been dropped, and replaced by Xerces-C++ (which has no further dependencies).
</li>
<li>
  Wt programs need to link against libwtfcgi.so, instead of libwt.so. In the
  future Wt will also support different web-connnector systems besides
  FastCGI.
</li>
<li>
  The signatures of wmain() and WApplication constructor have changed:
  new signatures are:
  <ul>
    <li><samp>int wmain(const WEnvironment&amp; env)</samp></li>
    <li><samp>WApplication::WApplication(const WEnvironment&amp; env)</samp></li>
 </ul>
</li>
</ul>

<h3>Other changes:</h3>

<ul>
  <li>Support for unicode is implemented, but perhaps needs more testing
  by non-Western people ? Only UTF-8 is supported currently.</li>
  <li>Addition of a WTimer class -- see mission example.</li>
  <li>Many bug fixes which should make Wt more robust against illegal CGI
    requests (which are ignored), and now Wt should exit cleanly in more
    (all?) circumstances.</li>
  <li>Addition of feed-back for pending AJAX requests (does not work yet on
    IE).</li>
  <li>Support for style sheets is improved: now inline decoration styles
    will override style sheet styles. See hangman or treelist examples.</li>
  <li>The browser can be redirected to a new page. This is useful when the
    application is terminated -- or to change during the application from
    HTTP to HTTPS and back.</li>
  <li>WValidationStatus API has changed -- less complicated now.</li>
</ul>

</body>
</html>
